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   207篇
  免费   13篇
  国内免费   4篇
  2023年   6篇
  2022年   1篇
  2021年   7篇
  2020年   3篇
  2019年   10篇
  2018年   6篇
  2017年   6篇
  2016年   4篇
  2015年   4篇
  2014年   4篇
  2013年   13篇
  2012年   9篇
  2011年   4篇
  2010年   5篇
  2009年   5篇
  2008年   7篇
  2007年   9篇
  2006年   13篇
  2005年   6篇
  2004年   9篇
  2003年   8篇
  2002年   5篇
  2001年   1篇
  1999年   2篇
  1998年   5篇
  1997年   6篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   3篇
  1991年   6篇
  1990年   4篇
  1989年   7篇
  1988年   3篇
  1987年   3篇
  1985年   9篇
  1982年   7篇
  1981年   5篇
  1979年   5篇
  1978年   2篇
  1976年   2篇
  1975年   1篇
排序方式: 共有224条查询结果,搜索用时 98 毫秒
221.
《Neuron》2023,111(2):256-274.e10
  1. Download : Download high-res image (143KB)
  2. Download : Download full-size image
  相似文献   
222.
Abstract. The regulation of Juvenile Hormone (JH) HI biosynthesis and release by the corpora allata (CA) was studied in final instar male and female larvae of the earwig, Euborellia annulipes , using a radiochemical assay in vitro. In males, maximal biosyntiiesis of JH IH occurred on day 1, then declined to virtually undetectable levels for the following 12 days of the stadium, and finally increased on days 14–16. In females, peaks of biosynthesis were detected on days 0–1 and on day 12. A further investigation of the 12-day-old larvae demonstrated mat in nonmoulting males and females, JH UJ biosynthesis was undetectable. However, for males and females undergoing ecdysis, the biosynthesis of JH III was detected and quantified.
The addition of 60 μM farnesoic acid to the incubation medium significantly increased the production of JH III by CA taken from females from day 8 until the end of the stadium. Glands from 12-day old females that had initiated ecdysis were stimulated by farnesoic acid. By contrast, we could detect no stimulation of production of JH III by farnesoic acid in CA taken from males, even very late in the stadium. CA from newly emerged adult males and females were more active than those of larvae, and were greatly stimulated by farnesoic acid. CA from females immediately after emergence were stimulated significantly more by farnesoic acid man were glands from newly emerged males. These results suggest fundamental differences in the synmetic activity of CA for males and females in this insect.  相似文献   
223.
Summary Ovarian (OM) and extraovarian (EM) mesothelia represent a common source of gynecologic malignancies with yet unclear pathogenesis. Ovulation triggers a finite wave of DNA synthesis and morphogenesis only in native OM cells, probably through the activation of intraovarian growth factors. To evaluate their growth response to such factors, OM and EM cells were obtained from estrous New Zealand white rabbits by enzymatic dispersion and unit gravity sedimentation. Cell cultures were maintained in serumless, fibronectin-rich, HL-1 medium without or with rabbit corpora lutea tissue extracts (CLE). The growth effects of CLE were evaluated by measuring percent changes in cell number relative to controls (CCN), cell population doublings (CPD), cell population doubling time in hours (CPDT). After 7.5 days, CLE enhanced (P<0.001) the growth of both OM and EM cells, which exhibited, respectively, a CCN of 214 and 257%; a CPD of 2.89 and 2.87; and a CPDT of 54.39 and 59.49. CLE-treated OM and EM cells were smaller, formed more cohesive monolayers, and exhibited more frequent and diffuse microvilli than control cells. These data show a similar in vitro response of OM and EM cells to luteal growth factors, suggesting that the lack of postovulatory morphogenesis in native extraovarian mesothelia is due to the spatially restricted activity of intraovarian growth factors.  相似文献   
224.
金秀东  田淑君 《生理学报》1994,46(5):514-519
参照我室Wang Xiao-Ning的黄体细胞制备方法,制成大鼠黄体细胞悬浮液,经蔗糖密度梯度离心分离大,小黄体细胞,经60min预培灌后,每10min收集一次培灌液,用RIA测定其中孕酮含量,实验结果表明,在培灌系统中,大黄体细胞的基础孕酮分泌量明显高于小黄体细胞,但小黄体地hCG的敏感性强于大黄体细胞,不同剂量的酪氨酸对hCG致大,小黄体细胞孕酮生成有不同程度的抑制,对小黄体细胞的抑制作用较为  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