全文获取类型
收费全文 | 1817篇 |
免费 | 141篇 |
专业分类
1958篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 15篇 |
2021年 | 36篇 |
2020年 | 32篇 |
2019年 | 41篇 |
2018年 | 32篇 |
2017年 | 28篇 |
2016年 | 53篇 |
2015年 | 95篇 |
2014年 | 120篇 |
2013年 | 136篇 |
2012年 | 185篇 |
2011年 | 236篇 |
2010年 | 136篇 |
2009年 | 75篇 |
2008年 | 122篇 |
2007年 | 139篇 |
2006年 | 111篇 |
2005年 | 79篇 |
2004年 | 88篇 |
2003年 | 59篇 |
2002年 | 60篇 |
2001年 | 14篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有1958条查询结果,搜索用时 0 毫秒
991.
992.
Tip-enhanced Raman scattering (TERS) enables the label-free investigation of biochemical interfaces with nanometer lateral resolution by combining the benefits of the intrinsic molecular specificity of Raman spectroscopy, the sensitivity because of signal enhancing capabilities of plasmonic nanoparticles, and the precision of scanning probe microscopy. The structural differentiation of constituents based on inherent molecular information is possible even down to a few nanometer spatial resolution and consequently, nucleobases, proteins, lipids, and carbohydrates can be identified and localized in a single measurement. This has been shown in the last few years for different biological samples ranging from single DNA strand investigations to cell membrane studies. 相似文献
993.
Rotival M Zeller T Wild PS Maouche S Szymczak S Schillert A Castagné R Deiseroth A Proust C Brocheton J Godefroy T Perret C Germain M Eleftheriadis M Sinning CR Schnabel RB Lubos E Lackner KJ Rossmann H Münzel T Rendon A;Cardiogenics Consortium Erdmann J Deloukas P Hengstenberg C Diemert P Montalescot G Ouwehand WH Samani NJ Schunkert H Tregouet DA Ziegler A Goodall AH Cambien F Tiret L Blankenberg S 《PLoS genetics》2011,7(12):e1002367
994.
Li Zhang Michael Buerke Michael Lautenschläger Li Chen Adrian Frister Axel Schlitt Tanja Luther Nan Song Britt Hofmann Stefan Rose‐John Rolf‐Edgar Silber Ursula Müller‐Werdan Karl Werdan 《Journal of cellular and molecular medicine》2011,15(4):994-1004
Inflammatory pathways are involved in the development of atherosclerosis. Interaction of vessel wall cells and invading monocytes by cytokines may trigger local inflammatory processes. 3‐Hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitors (statins) are standard medications used in cardiovascular diseases. They are thought to have anti‐inflammatory capacities, in addition to their lipid‐lowering effects. We investigated the anti‐inflammatory effect of statins in the cytokine‐mediated‐interaction‐model of human vascular smooth muscle cells (SMC) and human mononuclear cells (MNC). In this atherosclerosis‐related inflammatory model LPS (lipopolysaccharide, endotoxin), as well as high mobility group box 1 stimulation resulted in synergistic (i.e. over‐additive) IL‐6 (interleukin‐6) production as measured in ELISA. Recombinant IL‐1, tumour necrosis factor‐α and IL‐6 mediated the synergistic IL‐6 production. The standard anti‐inflammatory drugs aspirin and indomethacin (Indo) reduced the synergistic IL‐6 production by 60%. Simvastatin, atorvastatin, fluvastatin or pravastatin reduced the IL‐6 production by 53%, 50%, 64% and 60%, respectively. The inhibition by the statins was dose dependent. Combination of statins with aspirin and/or Indo resulted in complete inhibition of the synergistic IL‐6 production. The same inhibitors blocked STAT3 phosphorylation, providing evidence for an autocrine role of IL‐6 in the synergism. MNC from volunteers after 5 day aspirin or simvastatin administration showed no decreased IL‐6 production, probably due to drug removal during MNC isolation. Taken together, the data show that anti‐inflammatory functions (here shown for statins) can be sensitively and reproducibly determined in this novel SMC/MNC coculture model. These data implicate that statins have the capacity to affect atherosclerosis by regulating cytokine‐mediated innate inflammatory pathways in the vessel wall. 相似文献
995.
Allozyme variation has been and continues to be a major source of information on the level of genetic variation among plant
species. Deciphering the molecular basis of electrophoretic variation is essential for understanding the forces affecting
the protein level variation. In this study, the relationship between allozyme heterozygosity and nucleotide diversity in plants
is investigated among and within species. Allozyme and nucleotide diversity in 27 plant species was reviewed. At the multilocus
level, the two methods are congruent: a clear correlation between the two measures of genetic diversity among plant species
was observed, strengthening the view that effective population size is the major determinant of genome-wide diversity. Nucleotide
diversity at six allozyme coding genes (6pgdB, aco, gdh, gotC, mdhA, and mdhB) in conifer Pinus sylvestris was investigated jointly with electrophoretic data. Single non-synonymous charge-changing mutations were found together with
electrophoretic alleles that consequently were mutationally unique. Synonymous site nucleotide diversity (point estimate of
θ
W—0.009 per bp) and silent site divergence from Pinus pinaster at allozyme coding loci were at comparable levels with other loci in the species. Linkage disequilibrium was extensive compared
to earlier estimates from P. sylvestris and other trees, spanning several kilobases. Allozyme coding genes had an excess of closely related haplotypes whose frequency
has recently increased possibly as a result of partial selective sweeps or balancing selection, but complex demographic effects
cannot be excluded. 相似文献
996.
The genome of Akkermansia muciniphila, a dedicated intestinal mucin degrader, and its use in exploring intestinal metagenomes 总被引:1,自引:0,他引:1
van Passel MW Kant R Zoetendal EG Plugge CM Derrien M Malfatti SA Chain PS Woyke T Palva A de Vos WM Smidt H 《PloS one》2011,6(3):e16876
Background
The human gastrointestinal tract contains a complex community of microbes, fulfilling important health-promoting functions. However, this vast complexity of species hampers the assignment of responsible organisms to these functions. Recently, Akkermansia muciniphila, a new species from the deeply branched phylum Verrucomicrobia, was isolated from the human intestinal tract based on its capacity to efficiently use mucus as a carbon and nitrogen source. This anaerobic resident is associated with the protective mucus lining of the intestines.Methodology/Principal Findings
In order to uncover the functional potential of A. muciniphila, its genome was sequenced and annotated. It was found to contain numerous candidate mucinase-encoding genes, but lacking genes encoding canonical mucus-binding domains. Numerous phage-associated sequences found throughout the genome indicate that viruses have played an important part in the evolution of this species. Furthermore, we mined 37 GI tract metagenomes for the presence, and genetic diversity of Akkermansia sequences. Out of 37, eleven contained 16S ribosomal RNA gene sequences that are >95% identical to that of A. muciniphila. In addition, these libraries were found to contain large amounts of Akkermansia DNA based on average nucleotide identity scores, which indicated in one subject co-colonization by different Akkermansia phylotypes. An additional 12 libraries also contained Akkermansia sequences, making a total of ∼16 Mbp of new Akkermansia pangenomic DNA. The relative abundance of Akkermansia DNA varied between <0.01% to nearly 4% of the assembled metagenomic reads. Finally, by testing a large collection of full length 16S sequences, we find at least eight different representative species in the genus Akkermansia.Conclusions/Significance
These large repositories allow us to further mine for genetic heterogeneity and species diversity in the genus Akkermansia, providing novel insight towards the functionality of this abundant inhabitant of the human intestinal tract. 相似文献997.
Pagani I Chertkov O Lapidus A Lucas S Del Rio TG Tice H Copeland A Cheng JF Nolan M Saunders E Pitluck S Held B Goodwin L Liolios K Ovchinikova G Ivanova N Mavromatis K Pati A Chen A Palaniappan K Land M Hauser L Jeffries CD Detter JC Han C Tapia R Ngatchou-Djao OD Rohde M Göker M Spring S Sikorski J Woyke T Bristow J Eisen JA Markowitz V Hugenholtz P Klenk HP Kyrpides NC 《Standards in genomic sciences》2011,4(2):154-162
Marivirga tractuosa (Lewin 1969) Nedashkovskaya et al. 2010 is the type species of the genus Marivirga, which belongs to the family Flammeovirgaceae. Members of this genus are of interest because of their gliding motility. The species is of interest because representative strains show resistance to several antibiotics, including gentamicin, kanamycin, neomycin, polymixin and streptomycin. This is the first complete genome sequence of a member of the family Flammeovirgaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,511,574 bp long chromosome and the 4,916 bp plasmid with their 3,808 protein-coding and 49 RNA genes are a part of the Genomic Encyclopedia of Bacteria and Archaea project. 相似文献
998.
Anderson I Sikorski J Zeytun A Nolan M Lapidus A Lucas S Hammon N Deshpande S Cheng JF Tapia R Han C Goodwin L Pitluck S Liolios K Pagani I Ivanova N Huntemann M Mavromatis K Ovchinikova G Pati A Chen A Palaniappan K Land M Hauser L Brambilla EM Ngatchou-Djao OD Rohde M Tindall BJ Göker M Detter JC Woyke T Bristow J Eisen JA Markowitz V Hugenholtz P Klenk HP Kyrpides NC 《Standards in genomic sciences》2011,4(3):322-330
Nitratifractor salsuginis Nakagawa et al. 2005 is the type species of the genus Nitratifractor, a member of the family Nautiliaceae. The species is of interest because of its high capacity for nitrate reduction via conversion to N(2) through respiration, which is a key compound in plant nutrition. The strain is also of interest because it represents the first mesophilic and facultatively anaerobic member of the Epsilonproteobacteria reported to grow on molecular hydrogen. This is the first completed genome sequence of a member of the genus Nitratifractor and the second sequence from the family Nautiliaceae. The 2,101,285 bp long genome with its 2,121 protein-coding and 54 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project. 相似文献
999.
Kallimanis A Karabika E Mavromatis K Lapidus A Labutti KM Liolios K Ivanova N Goodwin L Woyke T Velentzas AD Perisynakis A Ouzounis CC Kyrpides NC Koukkou AI Drainas C 《Standards in genomic sciences》2011,5(1):144-153
Mycobacterium sp.Spyr1 is a newly isolated strain that occurs in a creosote contaminated site in Greece. It was isolated by an enrichment method using pyrene as sole carbon and energy source and is capable of degrading a wide range of PAH substrates including pyrene, fluoranthene, fluorene, anthracene and acenapthene. Here we describe the genomic features of this organism, together with the complete sequence and annotation. The genome consists of a 5,547,747 bp chromosome and two plasmids, a larger and a smaller one with sizes of 211,864 and 23,681 bp, respectively. In total, 5,588 genes were predicted and annotated. 相似文献
1000.
Anderson I Wirth R Lucas S Copeland A Lapidus A Cheng JF Goodwin L Pitluck S Davenport K Detter JC Han C Tapia R Land M Hauser L Pati A Mikhailova N Woyke T Klenk HP Kyrpides N Ivanova N 《Standards in genomic sciences》2011,5(1):12-20
Staphylothermus hellenicus belongs to the order Desulfurococcales within the archaeal phylum Crenarchaeota. Strain P8(T) is the type strain of the species and was isolated from a shallow hydrothermal vent system at Palaeochori Bay, Milos, Greece. It is a hyperthermophilic, anaerobic heterotroph. Here we describe the features of this organism together with the complete genome sequence and annotation. The 1,580,347 bp genome with its 1,668 protein-coding and 48 RNA genes was sequenced as part of a DOE Joint Genome Institute (JGI) Laboratory Sequencing Program (LSP) project. 相似文献