1. 介绍microsporidia 是一不寻常的和不同的群体intracellular 寄生虫。 他们时常被谈到如远古的由於‘原始人的 eukaryotes' 例如 prokaryoticlike 的特征70S ribosome 和小的 genome 大小 [1,2]. 方面他们的细胞组织也是不寻常的。 Microsporidiaamitochondrial 是吗, 虽然这可能是穿越中级的损失 [3]. 他们有一套原始的 Golgi 装置而且核子的区分没有分解被引起核子的信封 [4]. 一数字的序列分析microsporidian 基因提议他们可能是讲到真菌 [5] 而且这被特性为～作证例如 壳质的户外运动墙壁和 intranuclear 区分。 他们是一个广大的和不同的团体并且是已知的传染主人种从原生生物到人排列。 他们的到处存在的出现在主人 phyla 中借支持到他们是远古的并且意谓那的争论他们为主人–寄生虫的研究构成一个优良的团体进化。 ～的关键 microsporidia 谎言的成功在那他们的传输策略的各式个样和柔性和生活循环。 Microsporidia 是最小的, 最简单的 eukaryotes 。 在那边的生活周期里面是二基本 morphological表格， meront 或 proliferative 阶段和户外运动或传输阶段 [6]. meront 有简单的格状自动化结构。 它的血浆薄膜是在直接的连络中由于主人细胞质和有证据那寄生虫功绩主办细胞器官如营养物的一个来源 [4]. 那户外运动有厚, 使生存能够的反抗墙壁在extracellular 环境和一个复杂的挤出斡旋侵犯的装置藉由注射 sporoplasm直接的进入主人细胞的细胞质之内 [6]. 成功的主人–主人传输对生存是紧要关头的使负义务,intracellular 寄生虫。 在里面那microsporidia 那里是不同的策略范围为在主人人口中的寄生虫维护。 这些包括直接的和间接的生活周期和水平线的使用而且垂直的传输。 Microsporidia 传染一宽的包括许多节肢动物种的主人范围是藉着季节的人口坠毁的特色。 许多特性microsporidia 许可证寄生虫生存当在栖息地中主人不不断地出现的时候。
Cell (biology)The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as a living thing, and is often called the building block of life.[1] Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.[2]In 1835 before the final cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[3]The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.[4][edit] General principles Mouse cells grown in a culture dish. These cells grow in large clumps, but each individual cell is about 10 micrometres acrossEach cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these cells have several different abilities:[5]Reproduction by cell division: (binary fission/mitosis or meiosis). Use of enzymes and other proteins coded for by DNA genes and made via messenger RNA intermediates and ribosomes. Metabolism, including taking in raw materials, building cell components, converting energy, molecules and releasing by-products. The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy is released and then used in metabolic pathways. Response to external and internal stimuli such as changes in temperature, pH or levels of nutrients. Cell contents are contained within a cell surface membrane that is made from a lipid bilayer with proteins embedded in it. Some prokaryotic cells contain important internal membrane-bound compartments,[6] but eukaryotic cells have a specialized set of internal membrane compartments.[edit] Anatomy of cellsThere are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually independent, while eukaryotic cells are often found in multicellular organisms.[edit] Prokaryotic cellsMain article: Prokaryote Diagram of a typical prokaryotic cellThe prokaryote cell is simpler than a eukaryote cell, lacking a nucleus and most of the other organelles of eukaryotes. There are two kinds of prokaryotes: bacteria and archaea; these share a similar overall prokaryotic cell has three architectural regions:on the outside, flagella and pili project from the cell's surface. These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells; enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma membrane though some bacteria also have a further covering layer called a capsule. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter. Though most prokaryotes have a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermoplasma (archaea)). The cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and finally bursting (cytolysis) from osmotic pressure against a hypotonic environment. Some eukaryote cells (plant cells and fungi cells) also have a cell wall; inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions. A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes Lyme disease). Though not forming a nucleus, the DNA is condensed in a nucleoid. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Plasmids enable additional functions, such as antibiotic resistance. [edit] Eukaryotic cellsMain article: Eukaryote Diagram of a typical animal (eukaryotic) cell, showing subcellular :(1) nucleolus(2) nucleus(3) ribosome(4) vesicle(5) rough endoplasmic reticulum (ER)(6) Golgi apparatus(7) Cytoskeleton(8) smooth endoplasmic reticulum(9) mitochondria(10) vacuole(11) cytoplasm(12) lysosome(13) centrioles within centrosomeEukaryotic cells are about 15 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Most important among these is the presence of a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell's DNA. It is this nucleus that gives the eukaryote its name, which means "true nucleus." Other differences include:The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present. The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also contain some DNA. Many eukaryotic cells are ciliated with primary cilia. Primary cilia play important roles in chemosensation, mechanosensation, and thermosensation. Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7] Eukaryotes can move using motile cilia or flagella. The flagella are more complex than those of prokaryotes. Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes Typical organisms bacteria, archaea protists, fungi, plants, animals Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller) Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane DNA circular (usually) linear molecules (chromosomes) with histone proteins RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleusprotein synthesis in cytoplasm Ribosomes 50S+30S 60S+40S Cytoplasmatic structure very few structures highly structured by endomembranes and a cytoskeleton Cell movement flagella made of flagellin flagella and cilia containing microtubules; lamellipodia and filopodia containing actin Mitochondria none one to several thousand (though some lack mitochondria) Chloroplasts none in algae and plants Organization usually single cells single cells, colonies, higher multicellular organisms with specialized cells Cell division Binary fission (simple division) Mitosis (fission or budding)Meiosis Table 2: Comparison of structures between animal and plant cells Typical animal cell Typical plant cell Organelles Nucleus Nucleolus (within nucleus) Rough endoplasmic reticulum (ER) Smooth ER Ribosomes Cytoskeleton Golgi apparatus Cytoplasm Mitochondria Vesicles Lysosomes Centrosome Centrioles Vacuoles Nucleus Nucleolus (within nucleus) Rough ER Smooth ER Ribosomes Cytoskeleton Golgi apparatus (dictiosomes) Cytoplasm Mitochondria [edit] Subcellular components The cells of eukaryotes (left) and prokaryotes (right)All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, separates its interior from its environment, regulates what moves in and out (selectively permeable), and maintains the electric potential of the cell. Inside the membrane, a salty cytoplasm takes up most of the cell volume. All cells possess DNA, the hereditary material of genes, and RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machinery. There are also other kinds of biomolecules in cells. This article will list these primary components of the cell, then briefly describe their function.[edit] Cell membrane: A cell's defining boundaryMain article: Cell membraneThe cytoplasm of a cell is surrounded by a cell membrane or plasma membrane. The plasma membrane in plants and prokaryotes is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (hydrophobic fat-like molecules) and hydrophilic phosphorus molecules. Hence, the layer is called a phospholipid bilayer. It may also be called a fluid mosaic membrane. Embedded within this membrane is a variety of protein molecules that act as channels and pumps that move different molecules into and out of the cell. The membrane is said to be 'semi-permeable', in that it can either let a substance (molecule or ion) pass through freely, pass through to a limited extent or not pass through at all. Cell surface membranes also contain receptor proteins that allow cells to detect external signaling molecules such as hormones.[edit] Cytoskeleton: A cell's scaffoldMain article: Cytoskeleton Bovine Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green. Cell imaged on a fluorescent cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility. The eukaryotic cytoskeleton is composed of microfilaments, intermediate filaments and microtubules. There is a great number of proteins associated with them, each controlling a cell's structure by directing, bundling, and aligning filaments. The prokaryotic cytoskeleton is less well-studied but is involved in the maintenance of cell shape, polarity and cytokinesis.[8][edit] Genetic materialTwo different kinds of genetic material exist: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Most organisms use DNA for their long-term information storage, but some viruses (., retroviruses) have RNA as their genetic material. The biological information contained in an organism is encoded in its DNA or RNA sequence. RNA is also used for information transport (., mRNA) and enzymatic functions (., ribosomal RNA) in organisms that use DNA for the genetic code itself. Transfer RNA (tRNA) molecules are used to add specific amino acids during the process of protein genetic material is organized in a simple circular DNA molecule (the bacterial chromosome) in the nucleoid region of the cytoplasm. Eukaryotic genetic material is divided into different, linear molecules called chromosomes inside a discrete nucleus, usually with additional genetic material in some organelles like mitochondria and chloroplasts (see endosymbiotic theory).A human cell has genetic material in the nucleus (the nuclear genome) and in the mitochondria (the mitochondrial genome). In humans the nuclear genome is divided into 23 pairs of linear DNA molecules called chromosomes. The mitochondrial genome is a circular DNA molecule distinct from the nuclear DNA. Although the mitochondrial DNA is very small compared to nuclear chromosomes, it codes for 13 proteins involved in mitochondrial energy production as well as specific genetic material (most commonly DNA) can also be artificially introduced into the cell by a process called transfection. This can be transient, if the DNA is not inserted into the cell's genome, or stable, if it is. Certain viruses also insert their genetic material into the genome.[edit] OrganellesMain article: OrganelleThe human body contains many different organs, such as the heart, lung, and kidney, with each organ performing a different function. Cells also have a set of "little organs," called organelles, that are adapted and/or specialized for carrying out one or more vital are several types of organelles within an animal cell. Some (such as the nucleus and golgi apparatus) are typically solitary, while others (such as mitochondria, peroxisomes and lysosomes) can be numerous (hundreds to thousands). The cytosol is the gelatinous fluid that fills the cell and surrounds the and Chloroplasts – the power generators Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. Mitochondria play a critical role in generating energy in the eukaryotic cell. Mitochondria generate the cell's energy by the process of oxidative phosphorylation, utilizing oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two. Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through the process of photosynthesis, which utilizes solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed] Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell. Both of these organelles contain this DNA in circular plasmids, much like prokaryotic cells, strongly supporting the evolutionary theory of endosymbiosis; since these organelles contain their own genomes and have other similarities to prokaryotes, they are thought to have developed through a symbiotic relationship after being engulfed by a primitive cell.[citation needed] Ribosomes The ribosome is a large complex of RNA and protein molecules. They each consist of two subunits, and act as an assembly line where mRNA from the nucleus is used to synthesise proteins from amino acids. Ribosomes can be found either floating freely or bound to a membrane (the rough endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes).[9] Cell nucleus – a cell's information center The cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (transcription) occur. The nucleus is spherical in shape and separated from the cytoplasm by a double membrane called the nuclear envelope. The nuclear envelope isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing. During processing, DNA is transcribed, or copied into a special RNA, called mRNA. This mRNA is then transported out of the nucleus, where it is translated into a specific protein molecule. The nucleolus is a specialized region within the nucleus where ribosome subunits are assembled. In prokaryotes, DNA processing takes place in the cytoplasm. Diagram of a cell nucleus Endoplasmic reticulum – eukaryotes only The endoplasmic reticulum (ER) is the transport network for molecules targeted for certain modifications and specific destinations, as compared to molecules that will float freely in the cytoplasm. The ER has two forms: the rough ER, which has ribosomes on its surface and secretes proteins into the cytoplasm, and the smooth ER, which lacks them. Smooth ER plays a role in calcium sequestration and release. Golgi apparatus – eukaryotes only The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells. Vesicles that enter the Golgi apparatus are processed in a cis to trans direction, meaning they coalesce on the cis side of the apparatus and after processing pinch off on the opposite (trans) side to form a new vesicle in the animal cell.[citation needed] Diagram of an endomembrane system Lysosomes and Peroxisomes – eukaryotes only Lysosomes contain digestive enzymes (acid hydrolases). They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. Peroxisomes have enzymes that rid the cell of toxic peroxides. The cell could not house these destructive enzymes if they were not contained in a membrane-bound system. These organelles are often called a "suicide bag" because of their ability to detonate and destroy the cell.[citation needed] Centrosome – the cytoskeleton organiser The centrosome produces the microtubules of a cell – a key component of the cytoskeleton. It directs the transport through the ER and the Golgi apparatus. Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic spindle. A single centrosome is present in the animal cells. They are also found in some fungi and algae cells.[citation needed] Vacuoles Vacuoles store food and waste. Some vacuoles store extra water. They are often described as liquid filled space and are surrounded by a membrane. Some cells, most notably Amoeba, have contractile vacuoles, which are able to pump water out of the cell if there is too much water. [edit] Structures outside the cell wall[edit] CapsuleA gelatinous capsule is present in some bacteria outside the cell wall. The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules not marked by ordinary stain and can detected by special stain. The capsule is antigenic. The capsule has antiphagocytic function so it determines the virulence of many bacteria. It also plays a role in attachment of the organism to mucous membranes.[citation needed]
《科学》（英语：Science）是美国科学促进会（英语：American Association for the Advancement of Science，AAAS）出版的一份学术期刊，为全世界最权威的学术期刊之一。《科学》是发表最好的原始研究论文、以及综述和分析当前研究和科学政策的同行评议的期刊之一。该杂志于1880年由爱迪生投资1万美元创办，于1894年成为美国最大的科学团体“美国科学促进会”（American Association for the Advancement of Science ，AAAS)的官方刊物。全年共51期，为周刊，全球发行量超过150万份。
2018年12月，世界品牌实验室发布《2018世界品牌500强》榜单，科学排名第383。
材料类sci一区期刊：
sci期刊除了英文的，其实还有中文的，近几年不少中文的期刊被sci收录。接下来，根据这个问题详细的介绍一下。
1、《Journal of Materials Science Technology》The aims of this journal are to enhance the international exchange of scientific activities.
《Journal of Materials Science Technology》登世界各国的具有创新性和较高学术水平的原始性论文，该杂志已被誉为看中国材料研究发展趋势的一个窗口。所设栏目：letters、review articles、original papers、research notes、brief scientifie achievement.
2、《International Journal of Minerals Metallurgy and Materials》目前已经被多个国际著名检索机构收录，
在国内外享有较好声誉,《International Journal of Minerals Metallurgy and Materials》主要刊载矿业工程(Mineral)、
冶金工艺(Metallurgy)、材料科学(Materials)、信息与控制(Information)等领域的最新研究成果，所设栏目：矿业、冶金、材料。
3、《先进材料界面》英文期刊名称《Advanced Materials Interfaces》是由GERMANY出版。期刊ISSN：2196-7350，2017-2018最新影响因子：，2017-2018自引率：。
4、《应用粘土科学》英文期刊名称《APPLIED CLAY SCIENCE》由NETHERLANDS出版。出版周期：双月刊。期刊ISSN：0169-1317，2017-2018最新影响因子：，2017-2018自引率：20%。
5、《应用表面科学》英文期刊名称《APPLIED SURFACE SCIENCE》由NETHERLANDS出版，出版周期：半月刊。期刊ISSN：0169-4332，2017-2018最新影响因子：，2017-2018自引率：。
医学cscd核心期刊有：《中国中药》、《中国公共卫生》、《中华医院感染学》、《临床检验》、《药学学报》、《法医学》、《中草药》、《临床放射学》等，《实用放射学杂志》为cscd核心期刊。
核心期刊级别。
cscd期刊是核心期刊级别，cscd期刊是收录在cscd（中国科学引文数据库）里的期刊。cscd收录我国数学、物理、化学、天文学、地学、生物学、农林科学、医药卫生、工程技术和环境科学等领域出版的中英文科技核心期刊。
cscd是中国科学引文数据库，是国内七大核心期刊体系中的一类，学科方向上篇理科，在国内各领域中cscd刊物发表的文章认可度也是颇高的，特别是在个人晋升考核中，cscd刊物的作用和影响力仅次于北大核心期刊和南大核心期刊，cscd期刊的发表完全不需要英文写作，中文即可。
收录规模：
中国科学引文数据库来源期刊每两年遴选一次。每次遴选均采用定量与定性相结合的方法，定量数据来自于中国科学引文数据库，定性评价则通过聘请国内专家定性评估对期刊进行评审。定量与定性综合评估结果构成了中国科学引文数据库来源期刊。
2009-2010版本，中国科学引文数据库共遴选了核心库期刊669种；扩展库期刊：378种。
以上内容参考：百度百科-CSCD期刊
对照这个表格什么都明白了。期刊中,国内刊号后的A/B/C/D/E/F/G等意思那是期刊的分类号，期刊类别说明：“期刊类别”是国内统一连续出版物号的分类号。参考文献其他期刊分类号如下：A：马列主义、毛泽东思想、邓小平理论B：哲学、宗教C：社会科学总论D：政治、法律E：军事F：经济G：文化、科学、教育、体育G0：综合性文化G1：世界各国文化与文化事业G2：信息与知识传播G3：科学、科学研究G4：教育G8：体育H：语言、文字I：文学J：艺术K：历史、地理N：自然科学总论O：数理科学和化学O1：数学O3：力学O4：物理学O6：化学O7：晶体学P：天文学、地球科学Q：生物科学R：医药、卫生S：农业科学T：工业技术TB：一般工业技术TD：矿业工程TE：石油、天然气工业TF：冶金工业TG：金属学与金属工业TH：机械、仪表工业TJ：武器工业TK：能源与动力工程TL：原子能技术TM：电工技术TN：无线电电子学、电信技术TP：自动化技术、计算机技术TQ：化学工程TS：轻工业、手工业TU：建筑科学TV：水利工程U：交通运输V：航空、航天X：环境科学、安全科学Z：综合类
第一级-T类：特种刊物论文，指在《SCIENCE》和《NATURE》两本期刊上发表的论文。
第二级-A类：权威的核心期刊，指的是国际通用的SCIE、EI、ISTP、SSCI、A&HCI收录检索系统的论文(中国科学技术信息研究所检索为准)，或同一主题发表在国内中文核心期刊的权威，论文中不包含其他报告总结。
第三级-B类：重要核心刊物论文，指在国外核心期刊上刊登的论文(见《国外科技核心期刊手册》)或在国内同一学科的中文核心期刊中具有重要影响的刊物上发表的论文。
第四级-C类：一般核心刊物论文，指《全国中文核心期刊要目总览?北大图书馆2004版》刊物上发表的论文。
第五级-D类：一般公开刊物论文，指在国内公开发行的刊物上(有期刊号“CN”“ISSN” ，有邮发代号)发表的论文。
第六级-E类：受限公开刊物论文，指在国内公开发行的但受发行限制的刊物上(仅有期刊号、无邮发代号)发表的论文。
《求知导刊》是正规期刊。《求知导刊》是经国家新闻出版总署批准登记，广西壮族自治区新闻出版局主管、广西出版杂志社主办的全国优秀学术刊物（月刊），国内外公开发行。
补充资料： 《求知导刊》于2013年正式发刊，属于一般的普通中文期刊，未被核心期刊数据库收录。其基本信息如下：主办单位：广西出版杂志社；出版周期：半月；ISSN：2095-624X；CN：45-1393/N；出版地：广西壮族自治区南宁市；语种：中文；开本：大16开；邮发代号：48-128；创刊时间：2013。
核心论文期刊如下：
1、南大核心期刊：
"中文社会科学引文索引"（CSSCI）由南京大学中国社会科学研究评价中心开发研制而成CSSCI来源文献检索界面，收录包括法学、管理学、经济学、历史学、政治学等在内的25大类的500多种学术期刊。
2、北大核心期刊：
又叫中文核心，《中文核心期刊要目总览》是由北京大学图书馆及北京十几所高校图书馆众多期刊工作者及相关单位专家参加的研究项目，项目研究成果以印刷型图书形式出版，此前已由北京大学出版社出了八版。
3、统计源期刊（又称“中国科技核心期刊”）：
中国科学技术信息研究所“中国科技论文统计源期刊”，也叫科技核心，分为自然科学卷和社会科学卷，期刊较多。
4、中国社会科学院文献信息中心“中国人文社会科学核心期刊”：
中国社会科学院文献信息中心1996年开始进行人文社会科学文献计量研究工作， 建有“社会科学论文统计分析数据库”、“中国人文社会科学引文数据库”、社科论文摘转量统计库。
5、CSCD期刊：
中国科学院文献情报中心“中国科学引文数据库（CSCD）来源期刊”创建于1989年，收录我国数学、物理、化学、天文学、地学、生物学、农林科学、医药卫生、工程技术和环境科学等领域出版的中英文科技核心期刊和优秀期刊千余种。
1、自然Nature
《自然》杂志是世界上历史悠久的、最有名望的、科学界普遍关注的、国际性及跨学科的周刊类科学杂志，首版于1869年11月4日。
与当今大多数科学杂志专注于一个特殊的领域不同，《自然》是少数依然发表来自很多科学领域的一手研究论文的杂志，许多最重要、最前沿的研究结果都是以短讯的形式发表在《自然》上。2018年12月，世界品牌实验室发布“2018世界品牌500强”，《自然》排名第439。
2、新英格兰医学期刊Nejm
全称The New England Journal of Medicine，由美国麻州医学协会1811年创办的评审性质医学期刊和综合性医学期刊，始称《新英格兰医学与外科期刊》，经常被列为世界学术期刊医学领域中拥有最高影响因子之刊物。
期刊内容包含有：主题性之社论，原创性的论文，旁征博引性的评论性文章，即时短篇论文，案例报告，亦有一独特的报道项目称之为《临床医学影像》。
谷歌学术是一个可以免费搜索外文学术文章的搜索引擎，包括了世界上绝大部分出版的学术期刊，谷歌学术可了解有关某一领域的学术文献；了解某一作者的著述，并提供书目信息（引用时必需的图书出版信息或期刊论文的刊名、刊期信息）。部分文献可直接下载。
Elsevier（sciencedirect）是荷兰一家全球著名的学术期刊出版商，每年出版大量的学术图书和期刊，大部分期刊被SCI、SSCI、EI收录，是世界上公认的高品位学术期刊。
Web of Science是获取全球学术信息的重要数据库，它收录了全球13000多种权威的、高影响力的学术期刊，内容涵盖自然科学、工程技术、生物医学、社会科学、艺术与人文等领域。Web of Science 包括著名的三大引文索引数据库(SCI、SSCI、A&HCI)。
Wiley Online Library为全学科期刊全文数据库，出版物涵盖学科范围广泛——包括化学、物理学、工程学、农学、兽医学、食品科学、医学、护理学、口腔医学、生命科学、心理学、商业、经济学、社会科学、艺术、人类学等多个学科大约1600多种期刊，以及很多其它重要的跨学科领域的期刊。
SpringerLink是全球最大的在线科学、技术和医学(STM)领域学术资源平台。Springer 的电子图书数据库包括各种的Springer图书产品，如专著、教科书、手册、地图集、参考工具书、丛书等。具体学科涉及：数学、物理与天文学、化学、生命科学、医学、工程学、计算机科学、环境科学、地球科学、经济学、法律。
ProQuest商业信息、学术研究、应用科技数据库涉及商业管理、社会与人文科学、科学与技术、金融与税务、医药学等广泛领域。提供期刊、报纸、参考书、参考文献、书目、索引、地图集、绝版书籍、记录档案、博士论文和学者论文集等各种类型的信息服务，其中ProQuest Dissertations & Theses Global（PQDT Global）是目前世界上规模最大、使用最广泛的博硕士论文数据库。
PubMed 是一个免费的搜寻引擎，提供生物医学方面的论文搜寻以及摘要的数据库。它的数据库来源为MEDLINE。其核心主题为医学，但亦包括其他与医学相关的领域，像是护理学或者其他健康学科。提供指向全文提供者（付费或免费）的链接。
EI在全球的学术界、工程界、信息界中享有盛誉，是科技界共同认可的重要检索工具。涉及领域：机械工程、机电工程、船舶工程、制造技术、矿业、冶金、材料工程、金属材料、有色金属、陶瓷、塑料及聚合物工程等。
IEEE（Institute of Electrical & ElectronicsEngineers）是电气电子工程师协会IEEE和国际工程技术协会IET的全文库。IEEE致力于电气、电子、计算机工程和与科学有关的领域的开发和研究，在太空、计算机、电信、生物医学、电力及消费性电子产品等领域已制定了1300多个行业标准，现已发展成为具有较大影响力的国际学术组织。
百度学术于2014年6月上线，是百度旗下的免费学术资源搜索平台，提供海量中英文文献学术资源，涵盖各类学术期刊、学位、会议论文，部分文献可直接下载。
sci-hub专门免费下载外文文献，但网站经常换域名，有时不稳定，新域名也有卡顿打不开现象，而且没有收录新文献，目前2022年文献基本下不到。
学术文献下载器（)，把海量中外文献数据库资源整合一起，涵盖上面提到的文献数据库，文献资源庞大涉及全科，包括谷歌学术和sci-hub下载不了的文献。适合学校资源不够的高校生或者是单位没有数据库资源的科研人员查阅下载文献资料。