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   9138篇
  免费   656篇
  2024年   4篇
  2023年   69篇
  2022年   62篇
  2021年   326篇
  2020年   210篇
  2019年   261篇
  2018年   287篇
  2017年   248篇
  2016年   392篇
  2015年   576篇
  2014年   562篇
  2013年   698篇
  2012年   767篇
  2011年   735篇
  2010年   476篇
  2009年   417篇
  2008年   526篇
  2007年   539篇
  2006年   428篇
  2005年   384篇
  2004年   361篇
  2003年   314篇
  2002年   307篇
  2001年   114篇
  2000年   57篇
  1999年   77篇
  1998年   91篇
  1997年   68篇
  1996年   43篇
  1995年   43篇
  1994年   47篇
  1993年   30篇
  1992年   36篇
  1991年   28篇
  1990年   20篇
  1989年   16篇
  1988年   15篇
  1987年   15篇
  1986年   18篇
  1985年   17篇
  1984年   17篇
  1983年   15篇
  1982年   22篇
  1981年   6篇
  1980年   4篇
  1979年   6篇
  1978年   9篇
  1977年   5篇
  1974年   4篇
  1973年   4篇
排序方式: 共有9794条查询结果,搜索用时 15 毫秒
1.
Genome-wide analysis of the SET DOMAIN GROUP family in grapevine   总被引:1,自引:0,他引:1  
The SET DOMAIN GROUP (SDG) proteins represent an evolutionarily-conserved family of epigenetic regulators present in eukaryotes and are putative candidates for the catalysis of lysine methylation in histones. Plant genomes analyses of this family have been performed in arabidopsis, maize, and rice and functional studies have shown that SDG genes are involved in the control of plant development. In this work, we describe the identification and structural characterization of SDG genes in the Vitis vinifera genome. This analysis revealed the presence of 33 putative SDG genes that can be grouped into different classes, as it has been previously described for plants. In addition to the SET domain, the proteins identified possessed other domains in the different classes. As part of our study regarding the growth and development of grapevine, we selected eight genes and their expression levels were analyzed in representative vegetative and reproductive organs of this species. The selected genes showed different patterns of expression during inflorescence and fruit development, suggesting that they participate in these processes. Furthermore, we showed that the expression of selected SDGs changes during viral infection, using as a model Grapevine Leafroll Associated Virus 3-infected symptomatic grapevine leaves and fruits. Our results suggest that developmental changes caused by this virus could be the result of alterations in SDG expression.  相似文献   
2.
The potential for reducing the occurrence of shallow landslides through targeted reforestation of critical parts of a river basin is explored through mathematical modelling. Through the systematic investigation of land management options, modelling allows the optimum strategies to be selected ahead of any real intervention in the basin. Physically based models, for which the parameters can be evaluated using physical reasoning, offer particular advantages for predicting the effects of possible future changes in land use and climate. Typically a physically based landslide model consists of a coupled hydrological model (for soil moisture) and a geotechnical slope stability model, along with an impact model, such as basin sediment yield. An application of the SHETRAN model to the 65.8-km2 Guabalcón basin in central Ecuador demonstrates a technique for identifying the areas of a basin most susceptible to shallow landsliding and for quantifying the effects of different vegetation covers on landslide incidence. Thus, for the modelled scenario, increasing root cohesion from 300 to 1500 Pa causes a two-thirds reduction in the number of landslides. Useful information can be obtained even on the basis of imperfect data availability but model output should be interpreted carefully in the light of parameter uncertainty.  相似文献   
3.
4.
5.
6.
7.
8.
9.
10.
In this report we present data on the dispersion of a gene responsible for the plasmid-mediated resistance to fosfomycin among bacteria isolated from four hospitals and seven geographically separated domestic sewage treatment plants. Colony hybridization experiments, using a 0.85 kbp DNA fragment which carried the fosfomycin resistance determinant, have shown that the gene was present in isolates from three hospitals and six sewage plants although with different incidence and that it is carried by species of Enterobacteriaceae, Pseudomonas, Acinetobacter, Staphylococcus and Bacillus .  相似文献   
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