全文获取类型
收费全文 | 73517篇 |
免费 | 4843篇 |
国内免费 | 7篇 |
出版年
2023年 | 495篇 |
2022年 | 470篇 |
2021年 | 1294篇 |
2020年 | 1049篇 |
2019年 | 1206篇 |
2018年 | 2227篇 |
2017年 | 2064篇 |
2016年 | 2716篇 |
2015年 | 3539篇 |
2014年 | 3644篇 |
2013年 | 4846篇 |
2012年 | 5686篇 |
2011年 | 5171篇 |
2010年 | 3340篇 |
2009年 | 2693篇 |
2008年 | 3949篇 |
2007年 | 3696篇 |
2006年 | 3520篇 |
2005年 | 3015篇 |
2004年 | 2910篇 |
2003年 | 2622篇 |
2002年 | 2402篇 |
2001年 | 1677篇 |
2000年 | 1625篇 |
1999年 | 1287篇 |
1998年 | 628篇 |
1997年 | 469篇 |
1996年 | 460篇 |
1995年 | 430篇 |
1994年 | 321篇 |
1993年 | 314篇 |
1992年 | 647篇 |
1991年 | 563篇 |
1990年 | 508篇 |
1989年 | 500篇 |
1988年 | 477篇 |
1987年 | 432篇 |
1986年 | 406篇 |
1985年 | 405篇 |
1984年 | 410篇 |
1983年 | 275篇 |
1982年 | 263篇 |
1981年 | 200篇 |
1980年 | 207篇 |
1979年 | 275篇 |
1978年 | 240篇 |
1975年 | 222篇 |
1974年 | 249篇 |
1973年 | 247篇 |
1972年 | 215篇 |
排序方式: 共有10000条查询结果,搜索用时 687 毫秒
1.
2.
3.
4.
The complete primary structure of the functional site of erythrocyte protein 4.1 involved in spectrin-actin associations has been determined. The sequence of this domain, which contains 67 amino acids and has a molecular mass of 8045 daltons, has been obtained by NH2-terminal sequence analysis of an 8-kDa chymotryptic peptide, three endoproteinase lysine C-cleaved peptides and two peptides obtained by Staphylococcus aureus protease V8 cleavage. All peptides including the 8-kDa domain peptide were purified by reverse-phase high performance liquid chromatography. Antibodies against two different synthetic peptides of the 8-kDa domain are able to inhibit the association between protein 4.1, spectrin, and F-actin, corroborating that the 8-kDa domain is responsible for the formation of a ternary complex. A computer search of the 8-kDa sequence with the National Biomedical Research Foundation database did not detect any significant homologies to known sequences. Protein 4.1 is not related to any known proteins and may represent a new protein superfamily. 相似文献
5.
Sebastián Moran Miguel Vizoso Anna Martinez-Cardús Antonio Gomez Xavier Matías-Guiu Sebastián M Chiavenna Andrés G Fernandez Manel Esteller 《Epigenetics》2014,9(6):829-833
A formalin-fixed paraffin-embedded (FFPE) sample usually yields highly degraded DNA, which limits the use of techniques requiring high-quality DNA, such as Infinium Methylation microarrays. To overcome this restriction, we have applied an FFPE restoration procedure consisting of DNA repair and ligation processes in a set of paired fresh-frozen (FF) and FFPE samples. We validated the FFPE results in comparison with matched FF samples, enabling us to use FFPE samples on the Infinium HumanMethylation450 Methylation array. 相似文献
6.
7.
M del Mar Medina-Puerta A Garrido-Pertierra 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,83(1):215-220
The enzyme 6-phosphogluconate dehydrogenase (6-phospho-D-gluconate: NADP+ oxidoreductase, decarboxylating EC 1.1.1.44) from bass liver has been purified to over 95% of homogeneity by gel filtration, affinity and ion exchange chromatographies. The apparent molecular weight was estimated by gel filtration chromatography to about 100,000. Analysis of the enzyme on sodium dodecyl sulphate polyacrylamide gel electrophoresis showed to be a dimeric protein. The effect of pH and kinetic properties were studied. 相似文献
8.
"Pertussis toxin induces tachycardia and impairs the increase in blood pressure produced by alpha 2-adrenergic agonists" 总被引:4,自引:0,他引:4
Administration of purified pertussis toxin to rats induced persistent tachycardia, (observed in conscious rats but not after pithing); as little as 0.05 microgram/100 g produced a significant effect. Pertussis toxin-treatment did not affected the pressor response produced in the pithed rats by the alpha 2-adrenergic agonist methoxamine but markedly diminished the pressor effect of the alpha 2-adrenergic agonists clonidine and azepexole. A role of adenylate cyclase inhibition in the action of postsynaptic vascular alpha 2-adrenergic receptors is suggested. 相似文献
9.
10.
Páraic ó Cuív Rajesh Gupta Hareshwar P. Goswami Mark Morrison 《Applied and environmental microbiology》2013,79(19):6173-6175
Clostridium thermocellum encodes a cellulosomal, modular, and thermostable serine protease inhibitor (serpin), PinA. PinA stability but not inhibitory activity is affected by the Fn(III) and Doc(I) domains, and PinA is a broad inhibitor of subtilisin-like proteases and may play a key role in protecting the cellulosome from protease attack. 相似文献