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   40524篇
  免费   16391篇
  国内免费   4篇
  2023年   156篇
  2022年   348篇
  2021年   862篇
  2020年   2432篇
  2019年   3962篇
  2018年   4156篇
  2017年   4375篇
  2016年   4559篇
  2015年   4730篇
  2014年   4479篇
  2013年   5089篇
  2012年   2991篇
  2011年   2622篇
  2010年   3697篇
  2009年   2466篇
  2008年   1511篇
  2007年   1044篇
  2006年   935篇
  2005年   957篇
  2004年   938篇
  2003年   790篇
  2002年   784篇
  2001年   479篇
  2000年   360篇
  1999年   344篇
  1998年   179篇
  1997年   154篇
  1996年   122篇
  1995年   95篇
  1994年   85篇
  1993年   96篇
  1992年   94篇
  1991年   82篇
  1990年   84篇
  1989年   75篇
  1988年   61篇
  1987年   78篇
  1986年   43篇
  1985年   65篇
  1984年   70篇
  1983年   49篇
  1982年   45篇
  1981年   44篇
  1980年   25篇
  1979年   19篇
  1978年   30篇
  1977年   39篇
  1976年   21篇
  1975年   27篇
  1974年   27篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
83.
84.
85.
  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   
86.
Aims of this study were to analyze the long-term effects of postovulatory aging of mouse oocytes on 1) reproductive traits of parental (F(0)) and first (F(1))-generation females (pregnancy rate, gestation length, litter size, perinatal death, and sex ratio of offspring) and 2) developmental and behavioral variables of F(1) and second-generation (F(2)) offspring (birth weight and weight gain during preweaning development, postnatal day of attainment of immediate righting, spontaneous motor activity, and passive and active conditioned learning ability). Hybrid (C57BL/6JIco x CBA/JIco) females were artificially inseminated at 13 h (control group) or 22 h (oocyte-aged group) after GnRH injection. Experimental (oocyte-aged group) F(0) females exhibited lower pregnancy rate, shortened gestation length, decreased litter size, higher perinatal death of their pups, and increased percentage of male offspring compared to control F(0) females. Postovulatory aging of oocytes was also associated with increased number of growth-retarded pups, delayed development of the righting reflex, and higher spontaneous motor activity and emotionality of F(1) offspring. Postovulatory aging of F(0) oocytes did not affect birth weight, weight gain during preweaning development, passive and active conditioned learning ability of F(1) offspring, or reproductive traits of F(1) females or developmental and behavior variables of F(2) offspring.  相似文献   
87.
88.
Fourth-derivative spectrophotometry offers several advantages over classical absorption or difference spectrophotometry in examining the characteristics of aromatic amino acids in proteins. The basic principles of the technique and its applications are outlined.  相似文献   
89.
90.
The microtubule motor protein kinesin‐5 (Eg5) provides an outward force on centrosomes, which drives bipolar spindle assembly. Acute inhibition of Eg5 blocks centrosome separation and causes mitotic arrest in human cells, making Eg5 an attractive target for anti‐cancer therapy. Using in vitro directed evolution, we show that human cells treated with Eg5 inhibitors can rapidly acquire the ability to divide in the complete absence of Eg5 activity. We have used these Eg5‐independent cells to study alternative mechanisms of centrosome separation. We uncovered a pathway involving nuclear envelope (NE)‐associated dynein that drives centrosome separation in prophase. This NE‐dynein pathway is essential for bipolar spindle assembly in the absence of Eg5, but also functions in the presence of full Eg5 activity, where it pulls individual centrosomes along the NE and acts in concert with Eg5‐dependent outward pushing forces to coordinate prophase centrosome separation. Together, these results reveal how the forces are produced to drive prophase centrosome separation and identify a novel mechanism of resistance to kinesin‐5 inhibitors.  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