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   1053篇
  免费   61篇
  2021年   12篇
  2019年   6篇
  2018年   9篇
  2017年   7篇
  2016年   13篇
  2015年   20篇
  2014年   31篇
  2013年   44篇
  2012年   47篇
  2011年   62篇
  2010年   22篇
  2009年   27篇
  2008年   46篇
  2007年   40篇
  2006年   46篇
  2005年   54篇
  2004年   44篇
  2003年   52篇
  2002年   43篇
  2001年   41篇
  2000年   43篇
  1999年   26篇
  1998年   17篇
  1997年   10篇
  1996年   11篇
  1995年   15篇
  1994年   11篇
  1993年   14篇
  1992年   20篇
  1991年   24篇
  1990年   25篇
  1989年   21篇
  1988年   19篇
  1987年   20篇
  1986年   16篇
  1985年   17篇
  1984年   9篇
  1983年   14篇
  1982年   18篇
  1981年   12篇
  1980年   9篇
  1979年   6篇
  1978年   8篇
  1977年   5篇
  1975年   5篇
  1974年   7篇
  1973年   6篇
  1971年   6篇
  1967年   4篇
  1966年   5篇
排序方式: 共有1114条查询结果,搜索用时 31 毫秒
991.
992.
993.
It was investigated whether proteasome activity was implicated in susceptibility of human vascular smooth muscle cells (VSMCs) to Fas-mediated death. Human fetal aorta smooth muscle cells were treated with agonistic anti-Fas antibody (CH11) and proteasome inhibitors (MG115 or MG132) and then cell death was determined by morphology, viability, and DNA fragmentation. The present study reports that: (a) crosslinking of Fas receptor with anti-Fas antibody in the presence of proteasome inhibitor-induced death and DNA degradation in human VSMCs that were blocked by caspases inhibitor z-DEVD.fmk; (b) cotreatment with anti-Fas antibody and proteasome inhibitor activated caspase-3; (c) proteasome inhibitors did not influence expression of procaspase-8, procaspase-3, c-FLIP, and Bcl-2; and (d) proteasome inhibitors up-regulated Fas and FADD. The data indicate that proteasome activity is important in survival of VSMCs and provide the first evidence that proteasome is involved in Fas signal transduction. The present study proposes novel mechanism(s) by which VSMCs become susceptible to FasL.  相似文献   
994.
995.
996.
997.
998.
Although some polymethoxyflavones possess several important biological properties, including neuroprotective, anticancer, and anti-inflammatory ones, sudachitin, a polymethoxyflavone from Citrus sudachi, has been little studied. In this study, we found that sudachitin inhibited nitric oxide production by suppressing the expression of inducible nitric oxide synthase in lipopolysaccharide-stimulated macrophages, indicating that sudachitin has an anti-inflammatory effect.  相似文献   
999.
Methane oxidation coupled to denitrification is mediated by 'Candidatus Methylomirabilis oxyfera', which belongs to the candidate phylum NC10. The distribution of putative denitrifying methane-oxidizing bacteria related to "M. oxyfera" was investigated in a freshwater lake, Lake Biwa, Japan. In the surface layer of the sediment from a profundal site, a phylotype closely related to "M. oxyfera" was most frequently detected among NC10 bacteria in PCR analysis of the 16S rRNA gene. In the sediment, sequences related to "M. oxyfera" were also detected in a pmoA gene library. The presence of NC10 bacteria was also confirmed by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR indicated that the abundance of the "M. oxyfera"-related phylotype was higher in the upper layers of the profundal sediment. The horizontal distribution of the putative methanotrophs in lake sediment was also analyzed by DGGE, which revealed that their occurrence was restricted to deep water areas. These results agreed with those in a previous study of another freshwater lake, and suggested that the upper layer of the profundal sediments is the main habitat for denitrifying methanotrophs.  相似文献   
1000.
Small single‐celled Chaetoceros sp. are often widely distributed, but frequently overlooked. An estuarine diatom with an extremely high growth potential under optimal conditions was isolated from the Shinkawa‐Kasugagawa estuary in the eastern part of the Seto Inland Sea, western Japan. It was identified as Chaetoceros salsugineum based on morphological observations. This strain had a specific growth rate of 0.54 h?1 at 30°C under 700 μmol · m?2 · s?1 (about 30% of natural maximal summer light) with a 14:10 L:D cycle; there was little growth in the dark. However, under continuous light it grew at only 0.35 h?1 or a daily specific growth rate of 8.4 d?1. In addition, cell density, chlorophyll a, and particulate organic carbon concentrations increased by about 1000 times in 24 h at 30°C under 700 μmol · m?2 · s?1 with a 14:10 L:D cycle, showing a growth rate of close to 7 d?1. This very rapid growth rate may be the result of adaptation to this estuarine environment with high light and temperature. Thus, C. salsugineum can be an important primary producer in this estuary in summer and also an important organism for further physiological and genetic research.  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