首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1830篇
  免费   149篇
  国内免费   2篇
  2023年   3篇
  2022年   11篇
  2021年   34篇
  2020年   9篇
  2019年   29篇
  2018年   46篇
  2017年   32篇
  2016年   51篇
  2015年   87篇
  2014年   79篇
  2013年   120篇
  2012年   143篇
  2011年   121篇
  2010年   84篇
  2009年   75篇
  2008年   96篇
  2007年   137篇
  2006年   114篇
  2005年   106篇
  2004年   113篇
  2003年   112篇
  2002年   93篇
  2001年   9篇
  2000年   10篇
  1999年   24篇
  1998年   34篇
  1997年   29篇
  1996年   13篇
  1995年   18篇
  1994年   19篇
  1993年   15篇
  1992年   7篇
  1991年   13篇
  1990年   13篇
  1989年   7篇
  1988年   7篇
  1987年   5篇
  1986年   2篇
  1985年   5篇
  1984年   9篇
  1983年   8篇
  1982年   4篇
  1981年   6篇
  1980年   4篇
  1979年   10篇
  1978年   2篇
  1976年   6篇
  1975年   3篇
  1974年   2篇
  1964年   1篇
排序方式: 共有1981条查询结果,搜索用时 704 毫秒
81.
82.
Several H2-producing fermentative anaerobic bacteria including Clostridium, Klebsiella and Fusobacteria degraded octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) (36 microM) to formaldehyde (HCHO) and nitrous oxide (N2O) with rates ranging from 5 to 190 nmol h(-1)g [dry weight] of cells(-1). Among these strains, C. bifermentans strain HAW-1 grew and transformed HMX rapidly with the detection of the two key intermediates the mononitroso product and methylenedinitramine. Its cellular extract alone did not seem to degrade HMX appreciably, but degraded much faster in the presence of H2, NADH or NADPH. The disappearance of HMX was concurrent with the release of nitrite without the formation of the nitroso derivative(s). Results suggest that two types of enzymes were involved in HMX metabolism: one for denitration and the second for reduction to the nitroso derivative(s).  相似文献   
83.
84.
85.
Plant-parasitic nematodes Meloidogyne spp induce an elaborate permanent feeding site characterized by the redifferentiation of root cells into multinucleate and hypertrophied giant cells. We have isolated by a promoter trap strategy an Arabidopsis thaliana formin gene, AtFH6, which is upregulated during giant cell formation. Formins are actin-nucleating proteins that stimulate de novo polymerization of actin filaments. We show here that three type-I formins were upregulated in giant cells and that the AtFH6 protein was anchored to the plasma membrane and uniformly distributed. Suppression of the budding defect of the Saccharomyces cerevisiae bni1Delta bnr1Delta mutant showed that AtFH6 regulates polarized growth by controlling the assembly of actin cables. Our results suggest that AtFH6 might be involved in the isotropic growth of hypertrophied feeding cells via the reorganization of the actin cytoskeleton. The actin cables would serve as tracks for vesicle trafficking needed for extensive plasma membrane and cell wall biogenesis. Therefore, determining how plant parasitic nematodes modify root cells into giant cells represents an attractive system to identify genes that regulate cell growth and morphogenesis.  相似文献   
86.
87.
88.
The study of electron transfer between the copper protein rusticyanin (RCy) and the c(4)-cytochrome CYC(41) of the acidophilic bacterium Acidithiobacillus ferrooxidans has evidenced a remarkable decrease of RCy's redox potential upon complex formation. The structure of the CYC(41) obtained at 2.2 A resolution highlighted a specific glutamate residue (E121) involved in zinc binding as potentially playing a central role in this effect, required for the electron transfer to occur. EPR and stopped-flow experiments confirmed the strong inhibitory effect of divalent cations on CYC(41):RCy complex formation. A docking analysis of the CYC(41) and RCy structure allows us to propose a detailed model for the complex-induced tuning of electron transfer in agreement with our experimental data, which could be representative of other copper proteins involved in electron transfer.  相似文献   
89.
90.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号