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   2766篇
  免费   224篇
  国内免费   4篇
  2023年   11篇
  2022年   27篇
  2021年   56篇
  2020年   35篇
  2019年   34篇
  2018年   38篇
  2017年   36篇
  2016年   59篇
  2015年   114篇
  2014年   143篇
  2013年   148篇
  2012年   222篇
  2011年   213篇
  2010年   128篇
  2009年   126篇
  2008年   186篇
  2007年   175篇
  2006年   162篇
  2005年   177篇
  2004年   144篇
  2003年   145篇
  2002年   158篇
  2001年   22篇
  2000年   21篇
  1999年   34篇
  1998年   45篇
  1997年   23篇
  1996年   17篇
  1995年   19篇
  1994年   25篇
  1993年   19篇
  1992年   18篇
  1991年   17篇
  1990年   14篇
  1989年   17篇
  1988年   32篇
  1987年   11篇
  1986年   11篇
  1985年   14篇
  1984年   15篇
  1983年   7篇
  1982年   11篇
  1981年   14篇
  1979年   9篇
  1978年   6篇
  1977年   9篇
  1976年   5篇
  1975年   4篇
  1974年   5篇
  1973年   7篇
排序方式: 共有2994条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
  1. Download : Download high-res image (147KB)
  2. Download : Download full-size image
Highlights
  • •Sufficient tumor tissues are often unavailable large HLA peptidome discovery.
  • •Using patient derived xenograft (PDX) tumors can overcome this limitation.
  • •The large PDX HLA peptidomes expand significantly those of the original biopsies.
  • •The HLA peptidomes of the PDX tumors included many tumor antigens.
  相似文献   
5.
6.
7.
Egg mass shows large intraspecific variation in birds and is repeatable within individuals. The mechanisms underlying this variation are unknown. We hypothesized that measures of egg quality (the mass of yolk protein, yolk lipid, and albumen protein) would be positively correlated with the plasma pools of the yolk precursor vitellogenin, and the masses of the oviduct, metabolic machinery (liver, heart, lungs, kidneys, gizzard, small intestine and pancreas), and endogenous stores of protein and lipid. We tested these predictions in European Starlings Sturnus vulgaris collected at the peak of egg production effort. In contrast to our predictions, both yolk protein and yolk lipid were negatively correlated with plasma vitellogenin levels. Albumen protein was positively related to oviduct mass, but other aspects of body composition failed to explain variation in egg quality. Hence, while we observed correlations between egg composition and peripheral systems (circulating precursor pools and the oviduct), we found no evidence that egg quality is determined by more general processes, i.e., the supply and processing of nutrients.  相似文献   
8.
9.
The nucleotide sequences of the Escherichia coli genome between the glycogen biosynthetic genes glgB and glgC, and 1170 bp of DNA which follows glgA have been determined. The region between glgB and glgC contains an open reading frame (ORF) of 1521 bp which we call glgX. This ORF is capable of coding for an Mr 56 684 protein. The deduced amino acid (aa) sequence for the putative product shows significant similarity to the E. coli glycogen branching enzyme, and to several different glucan hydrolases and transferases. The regions of sequence similarity include residues which have been reported to be involved in substrate binding and catalysis by taka-amylase. This suggests that the proposed product may catalyze hydrolysis or glycosyltransferase reactions. The cloned region which follows glgA contains an incomplete ORF (1149 bp), glgY, which appears to encode 383 aa of the N terminus of glycogen phosphorylase, based upon sequence similarity with the enzyme from rabbit muscle (47% identical aa residues) and with maltodextrin phosphorylase from E. coli (37% identical aa residues). Results suggest that neither ORF is required for glycogen biosynthesis. The localization of glycogen biosynthetic and degradative genes together in a cluster may facilitate the regulation of these systems in vivo.  相似文献   
10.
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