全文获取类型
收费全文 | 355409篇 |
免费 | 22789篇 |
国内免费 | 1069篇 |
出版年
2018年 | 15839篇 |
2017年 | 14801篇 |
2016年 | 11766篇 |
2015年 | 4302篇 |
2014年 | 4865篇 |
2013年 | 6842篇 |
2012年 | 12093篇 |
2011年 | 22635篇 |
2010年 | 19113篇 |
2009年 | 14766篇 |
2008年 | 18502篇 |
2007年 | 20873篇 |
2006年 | 7017篇 |
2005年 | 7621篇 |
2004年 | 7595篇 |
2003年 | 7688篇 |
2002年 | 7272篇 |
2001年 | 12318篇 |
2000年 | 12233篇 |
1999年 | 9170篇 |
1998年 | 2677篇 |
1997年 | 2766篇 |
1996年 | 2716篇 |
1995年 | 2476篇 |
1994年 | 2429篇 |
1993年 | 2351篇 |
1992年 | 7199篇 |
1991年 | 7036篇 |
1990年 | 7067篇 |
1989年 | 6857篇 |
1988年 | 6372篇 |
1987年 | 6028篇 |
1986年 | 5354篇 |
1985年 | 5662篇 |
1984年 | 4472篇 |
1983年 | 3886篇 |
1982年 | 2684篇 |
1981年 | 2493篇 |
1980年 | 2304篇 |
1979年 | 4108篇 |
1978年 | 3134篇 |
1977年 | 2881篇 |
1976年 | 2827篇 |
1975年 | 3280篇 |
1974年 | 3496篇 |
1973年 | 3525篇 |
1972年 | 3729篇 |
1971年 | 3473篇 |
1970年 | 2538篇 |
1969年 | 2299篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
182.
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
183.
184.
185.
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
186.
Serological comparison of bovine T-mycoplasmas 总被引:1,自引:0,他引:1
187.
188.
David Skelly 《BMC biology》2010,8(1):136
A new study of divergence in freshwater fish provides strong evidence of rapid, temperature-mediated adaptation. This study
is particularly important in the ongoing debate over the extent and significance of evolutionary response to climate change
because divergence has occurred in relatively few generations in spite of ongoing gene flow and in the aftermath of a significant
genetic bottleneck, factors that have previously been considered obstacles to evolution. Climate change may thus be more likely
to foster contemporary evolutionary responses than has been anticipated, and I argue here for the importance of investigating
their possible occurrence. 相似文献
189.
AS it is not widely appreciated that diffusion within complex media can be strikingly and often qualitatively different from that in simple liquids such as water, there is confusion concerning transport processes across biological membranes1,2. We would like to draw attention to some fundamental differences between the diffusion process in simple liquids and that in more complex media-non-porous networks of hydrophobic polymers and biological membranes. 相似文献
190.
Morphological and genetic variation at microsatellite loci of Caucasian shrew Sorex satunini Ogn. is examined and compared with that of the common shrew S. araneus L. Genetic distance at microsatellite loci between the common shrew and Caucasian shrew proved to be threefold higher than
between chromosome races of the common shrew. The Caucasian shrew manifested low polymorphism in studies of both microsatellites
and morphometric mandibular traits. The heterozygote deficit was also typical. These properties may be a consequence of partial
isolation of the population and gene drift. 相似文献