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   2201篇
  免费   224篇
  国内免费   1篇
  2021年   32篇
  2020年   14篇
  2019年   15篇
  2018年   25篇
  2017年   13篇
  2016年   45篇
  2015年   72篇
  2014年   70篇
  2013年   87篇
  2012年   113篇
  2011年   123篇
  2010年   79篇
  2009年   75篇
  2008年   111篇
  2007年   114篇
  2006年   104篇
  2005年   90篇
  2004年   90篇
  2003年   80篇
  2002年   57篇
  2001年   65篇
  2000年   52篇
  1999年   59篇
  1998年   31篇
  1997年   13篇
  1996年   34篇
  1995年   31篇
  1994年   29篇
  1993年   32篇
  1992年   36篇
  1991年   32篇
  1990年   37篇
  1989年   24篇
  1988年   30篇
  1987年   31篇
  1986年   19篇
  1985年   21篇
  1984年   11篇
  1983年   13篇
  1981年   11篇
  1980年   13篇
  1979年   12篇
  1978年   10篇
  1975年   11篇
  1974年   8篇
  1973年   10篇
  1970年   11篇
  1969年   9篇
  1929年   8篇
  1927年   9篇
排序方式: 共有2426条查询结果,搜索用时 734 毫秒
991.
992.
Dissociated explants of 8-day-old embryonic chick cerebrum were cultured for up to 18 days. By the beginning of the 2nd week and thereafter, primary cultures of neurons exhibited characteristic differentiated morphology with an interconnecting neurofibrillary network that became increasingly ramified. Neurons in bipolar, tripolar or multipolar form could be demonstrated positively using a short modified silver impregnation method with potassium ferrocyanide.  相似文献   
993.
994.
Previous studies have reported abnormalities of thymic histology and cell numbers in 129/ ReJ-dy homozygous dystrophic mice, suggesting an association between murine muscular dystrophy and disorders of the immune system. The present study of C57BL/6J-dy2J and 129/ReJ-dy homozygous dystrophic mice included a thorough analysis of thymic development and histology, of T-cell function demonstrated by mitogen stimulation, mixed-leukocyte culture, and graft-vs-host assays, and of surface antigen expression as measured by flow microfluorometry. Although sporadic differences can be seen in some dystrophic mice, we find no evidence of consistent abnormalities of the immune system in murine muscular dystrophy. It does not seem possible, therefore, to study either the dy or the dy2J defect through analysis of lymphocytes. The feasibility of elucidating metabolic or membrane defects by utilizing cell populations other than those most conspicuously affected by a mutation with multisystem effects is discussed and our coincidental finding of a subpopulation of T cells with unusual antigenic properties is described.  相似文献   
995.
Schinus lentiscifolius Marchand has been used in folk medicine to treat immunoinflammatory related diseases, which are marked by OS and altered HSR. Our study aimed to evaluate OS and HSR in lymphocytes treated with S. lentiscifolius bark extracts. S. lentiscifolius barks were partitioned with solvents to obtain hexane (SL‐HEX), ethyl acetate (SL‐ACOET) and methanol (SL‐MEOH) extracts, and the presence of bioactive compounds was evaluated by thin layer chromatography. Total phenols were measured by the Folin–Ciocalteu method and flavonoids were identified by HPLC‐DAD‐ESI‐MS/MS. Antioxidant capacity was verified by DPPH method, cell viability by Trypan Blue method, lipid peroxidation by TBARS and HSP70 by immunoblotting. The SL‐ACOET extract presented higher content of phenolic compounds and antioxidant activity in vitro. It was able to reduce lipid peroxidation levels in lymphocytes induced by H2O2 and improved cell viability. The SL‐ACOET extract inhibited HSR by a decrease in both intracellular content and release of 70 kDa heat shock proteins (HSP70) and also by decrease extra‐to‐intracellular HSP70 ratio in lymphocytes submitted to heat shock (2 h, 41 °C). S. lentiscifolius bark extract has antioxidant activity and inhibitory effect on HSR probably due to the presence of polyphenols as the flavonoids quercetin and kaempferol.  相似文献   
996.
997.
998.
A constituent of Lebanese hashish was shown to be 2,6-dihydroxy-6′-isopropenyl-3′-methyl-4-n-pentyl-biphenyl, the aromatic analogue of cannabidiol. Synthesis and acid catalyzed conversion into cannabinol confirmed the assignment. This structure, cannabinodiol, was earlier erroneously assigned by others to a different compound; a suggestion for the correct structure of the latter product is given.  相似文献   
999.
A new cannabinoid, cannabicitran, was isolated from Lebanese hashish. This component was found to be identical to synthetic citrylidene-cannabis.  相似文献   
1000.
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