全文获取类型
收费全文 | 62769篇 |
免费 | 5913篇 |
国内免费 | 32篇 |
出版年
2022年 | 359篇 |
2021年 | 916篇 |
2020年 | 559篇 |
2019年 | 673篇 |
2018年 | 832篇 |
2017年 | 782篇 |
2016年 | 1249篇 |
2015年 | 2086篇 |
2014年 | 2365篇 |
2013年 | 3102篇 |
2012年 | 3807篇 |
2011年 | 3868篇 |
2010年 | 2522篇 |
2009年 | 2205篇 |
2008年 | 3165篇 |
2007年 | 3352篇 |
2006年 | 3201篇 |
2005年 | 3107篇 |
2004年 | 2973篇 |
2003年 | 2791篇 |
2002年 | 2740篇 |
2001年 | 944篇 |
2000年 | 839篇 |
1999年 | 946篇 |
1998年 | 897篇 |
1997年 | 696篇 |
1996年 | 615篇 |
1995年 | 550篇 |
1994年 | 554篇 |
1993年 | 567篇 |
1992年 | 714篇 |
1991年 | 648篇 |
1990年 | 643篇 |
1989年 | 608篇 |
1988年 | 587篇 |
1987年 | 566篇 |
1986年 | 529篇 |
1985年 | 578篇 |
1984年 | 635篇 |
1983年 | 550篇 |
1982年 | 620篇 |
1981年 | 621篇 |
1980年 | 513篇 |
1979年 | 496篇 |
1978年 | 502篇 |
1977年 | 420篇 |
1976年 | 454篇 |
1975年 | 358篇 |
1974年 | 417篇 |
1973年 | 394篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Peter W. Wilson Katie E. Osterday Aaron F. Heneghan Anthony D. J. Haymet 《The Journal of biological chemistry》2010,285(45):34741-34745
In this study, we examined the effects that antifreeze proteins have on the supercooling and ice-nucleating abilities of aqueous solutions. Very little information on such nucleation currently exists. Using an automated lag time apparatus and a new analysis, we show several dilution series of Type I antifreeze proteins. Our results indicate that, above a concentration of ∼8 mg/ml, ice nucleation is enhanced rather than hindered. We discuss this unexpected result and present a new hypothesis outlining three components of polar fish blood that we believe affect its solution properties in certain situations. 相似文献
142.
143.
Mutations in Aprataxin cause the neurodegenerative syndrome ataxia oculomotor apraxia type 1. Aprataxin catalyzes removal of adenosine monophosphate (AMP) from the 5′ end of a DNA strand, which results from an aborted attempt to ligate a strand break containing a damaged end. To gain insight into which DNA lesions are substrates for Aprataxin action in vivo, we deleted the Saccharomyces cerevisiae HNT3 gene, which encodes the Aprataxin homolog, in combination with known DNA repair genes. While hnt3Δ single mutants were not sensitive to DNA damaging agents, loss of HNT3 caused synergistic sensitivity to H2O2 in backgrounds that accumulate strand breaks with blocked termini, including apn1Δ apn2Δ tpp1Δ and ntg1Δ ntg2Δ ogg1Δ. Loss of HNT3 in rad27Δ cells, which are deficient in long-patch base excision repair (LP-BER), resulted in synergistic sensitivity to H2O2 and MMS, indicating that Hnt3 and LP-BER provide parallel pathways for processing 5′ AMPs. Loss of HNT3 also increased the sister chromatid exchange frequency. Surprisingly, HNT3 deletion partially rescued H2O2 sensitivity in recombination-deficient rad51Δ and rad52Δ cells, suggesting that Hnt3 promotes formation of a repair intermediate that is resolved by recombination. 相似文献
144.
145.
146.
147.
James H. Horton 《Brittonia》1963,15(3):177-203
148.
149.
James Fanning 《BMJ (Clinical research ed.)》1947,1(4498):371-373
150.
Michitaro Nagasawa James Amigo Chan Charles J. Sih 《Prostaglandins & other lipid mediators》1974,8(3):221-230
Prostaglandins E1, F1α and A2 were covalently joined to the surface of Sepharose as carboxamide linkages. The insolubilized prostaglandins were shown to function effectively in the purification of 15(S) -hydroxyprostaglandin dehydrogenase. 相似文献