全文获取类型
收费全文 | 503075篇 |
免费 | 55723篇 |
国内免费 | 343篇 |
出版年
2018年 | 9687篇 |
2017年 | 9447篇 |
2016年 | 9372篇 |
2015年 | 8428篇 |
2014年 | 9190篇 |
2013年 | 12918篇 |
2012年 | 17197篇 |
2011年 | 21899篇 |
2010年 | 15718篇 |
2009年 | 14743篇 |
2008年 | 18588篇 |
2007年 | 20485篇 |
2006年 | 12321篇 |
2005年 | 13300篇 |
2004年 | 12498篇 |
2003年 | 12105篇 |
2002年 | 11523篇 |
2001年 | 21746篇 |
2000年 | 21927篇 |
1999年 | 17402篇 |
1998年 | 6226篇 |
1997年 | 6489篇 |
1996年 | 6318篇 |
1995年 | 5703篇 |
1994年 | 5757篇 |
1993年 | 5597篇 |
1992年 | 13669篇 |
1991年 | 12979篇 |
1990年 | 12648篇 |
1989年 | 12514篇 |
1988年 | 11162篇 |
1987年 | 10789篇 |
1986年 | 9871篇 |
1985年 | 9647篇 |
1984年 | 8191篇 |
1983年 | 7088篇 |
1982年 | 5533篇 |
1981年 | 5002篇 |
1980年 | 4648篇 |
1979年 | 7689篇 |
1978年 | 5921篇 |
1977年 | 5425篇 |
1976年 | 5063篇 |
1975年 | 5375篇 |
1974年 | 5807篇 |
1973年 | 5655篇 |
1972年 | 5591篇 |
1971年 | 5175篇 |
1970年 | 3922篇 |
1969年 | 3851篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
291.
292.
293.
294.
S. T. Zakhidov T. L. Marshak E. A. Malolina A. Yu. Kulibin I.A. Zelenina S. M. Pavluchenkova V. M. Rudoi O. V. Dement’eva S. G. Skuridin Yu. M. Evdokimov 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2010,4(3):293-296
The effect of gold nanoparticles on mouse epididymal sperm has been studied using the model system of nuclear chromatin decondensation
in vitro. It is shown that the treatment of gametes, preliminary membrane-freed by sodium dodecyl sulfate, in the mediums
containing gold nanoparticles (with diameter ∼2.5 nm) in concentrations 1.0 × 1015 or 0.5 × 1015 particles/ml and following incubation in dithiothreitol solution (DTT) resulted in failure of chromatin decondensation process
and nucleus structure. We conclude that gold nanoparticles possess spermatotoxicity. The mechanism of cytotoxic effect of
gold nanoparticles may be related with their interaction with molecules of double-helix DNA. The model system studied in this
research is applicable for further investigations of cytotoxic effects of nanoparticles of different origin and made of different
metals. 相似文献
295.
296.
The dynamical structure of the RNA in alfalfa mosaic virus studied by 31P-nuclear magnetic resonance
The structure of the viral RNA in alfalfa mosaic virus (AlMV) was investigated by means of 31P-nuclear magnetic resonance (NMR). It was found that the 31P-NMR line width of AlMV Top a particles is significantly smaller than that of the larger Bottom particles. At low temperatures, the totational correlation time of the 31P nuclei essentially equals the tumbling rate of the virus particle, indicating that the RNA is contained rigidly inside the virion. At more elevated temperatures, the NMR line width sharpens more than expected on the basis of viscosity changes and the RNA exhibits internal mobility. The occurrence of internal mobility is paralleled by an increased internal mobility of the N-terminal part of the coat protein, as could be observed by 1H-NMR spectroscopy. The influence of EDTA on the 31P-NMR line width appeared to be negligible, which is in agreement with the idea that AlMV does not 'swell' like several other RNA-containing plant viruses. 相似文献
297.
298.
THE high-sulphur proteins of α-keratins, which constitute the non-filamentous matrix between the microfibrils, comprise several major groups of proteins, each group consisting of a number of closely related components. They are obtained in a soluble form by reduction of the disulphide bonds of wool and preferential extraction with alkaline thioglycollate at high ionic strength1. The thiol groups are subsequently stabilized by alkylation with iodoacetic acid. 相似文献
299.
300.
Serological comparison of bovine T-mycoplasmas 总被引:1,自引:0,他引:1