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   652篇
  免费   52篇
  704篇
  2022年   6篇
  2021年   4篇
  2020年   4篇
  2018年   10篇
  2017年   6篇
  2016年   9篇
  2015年   16篇
  2014年   18篇
  2013年   38篇
  2012年   30篇
  2011年   26篇
  2010年   27篇
  2009年   22篇
  2008年   23篇
  2007年   23篇
  2006年   31篇
  2005年   24篇
  2004年   31篇
  2003年   21篇
  2002年   31篇
  2001年   26篇
  2000年   25篇
  1999年   21篇
  1998年   11篇
  1997年   12篇
  1996年   5篇
  1995年   12篇
  1994年   8篇
  1993年   8篇
  1992年   11篇
  1991年   9篇
  1990年   21篇
  1989年   11篇
  1988年   14篇
  1987年   5篇
  1986年   9篇
  1985年   7篇
  1984年   8篇
  1983年   4篇
  1982年   5篇
  1981年   8篇
  1980年   10篇
  1979年   5篇
  1976年   3篇
  1975年   3篇
  1974年   5篇
  1972年   5篇
  1968年   3篇
  1967年   4篇
  1966年   6篇
排序方式: 共有704条查询结果,搜索用时 15 毫秒
61.
Errata     
The online version of the original article can be found at  相似文献   
62.
Midgut epithelium in Filientomon takanawanum is composed of epithelial cells and single, sporadic regenerative cells. In 80% of analyzed specimens midgut epithelial cells, as fat body and gonads, are infected with rickettsia-like microorganism. In non-infected specimens young and completely differentiated epithelial cells are distinguished among epithelial cells. Characteristic for midgut epithelial cells regionalization in organelles distribution is not observed. Autophagy is the sporadic process, but if the cytoplasm of epithelium cells possesses numerous spherites and sporadic autophagosomes, the apoptosis begins. Necrosis is observed sporadically.In the midgut epithelium cells of about 80% of analyzed specimens rickettsia-like microorganisms are observed. The more rickettsia-like microorganisms occur in the cytoplasm, the more autophagosomes are formed, and the process of apoptosis proceeds intensively.  相似文献   
63.
64.
Several engineered protein scaffolds have been developed recently to circumvent particular disadvantages of antibodies such as their large size and complex composition, low stability, and high production costs. We previously identified peptide aptamers containing one or two disulfide-bonds as an alternative ligand to the interleukin-6 receptor (IL-6R). Peptide aptamers (32 amino acids in length) were screened from a random peptide library by in vitro peptide selection using the evolutionary molecular engineering method "cDNA display". In this report, the antagonistic activity of the peptide aptamers were examined by an in vitro competition enzyme-linked immunosorbent assay (ELISA) and an IL-6-dependent cell proliferation assay. The results revealed that a disulfide-rich peptide aptamer inhibited IL-6-dependent cell proliferation with similar efficacy to an anti-IL-6R monoclonal antibody.  相似文献   
65.
66.
AimsInsulin/insulin-like growth factor-1 (IGF-1) signaling plays an important role in many biological processes. The class IA isoform of phosphoinositide 3-kinase (PI3K) is an important downstream effector of the insulin/IGF-1 signaling pathway. The aim of this study is to examine the effect of persistent activation of PI3K on gene expression and markers of cellular senescence in murine hearts.Main methodsTransgenic mice expressing a constitutively active PI3K in a heart-specific manner were analyzed at the ages of 3 and 20 months. Effects of persistent activation of PI3K on gene expression were comprehensively analyzed using microarrays.Key findingsUpon comprehensive gene expression profiling, the genes whose expression was increased included those for several heat shock chaperons. The amount and nuclear localization of a forkhead box O (FOXO) protein was increased. In addition, the gene expression of insulin receptor substrate-2 decreased, and that of phosphatase and tensin homolog deleted on chromosome ten (PTEN) increased, suggesting that the persistent activation of PI3K modified the expression of molecules of insulin/IGF-1 signaling. The expression of markers of cellular senescence, such as senescence-associated beta-galactosidase activity, cell cycle inhibitors, proinflammatory cytokines, and lipofuscin, did not differ between old wild-type and caPI3K mice.SignificanceThe persistent activation of PI3K modified the expression of molecules of insulin/IGF-1 signaling pathway in a transgenic mouse line. Markers of cellular senescence were not changed in the aged mutant mice.  相似文献   
67.
68.
69.
The Aspergillus oryzae glucoamylase-encoding gene glaB is expressed specifically and strongly only during solid-state cultivation (SSC). To elucidate the basis for the specificity, the glaB promoter was analyzed by electrophoretic gel mobility shift assay (EMSA) which indicated two protein-binding elements from ?382 to ?353 and from ?332 to ?313. To confirm that these regions contained cis-elements, deletion analysis of the promoter was undertaken using β-glucuronidase as a reporter. The results of the deletion analysis were consistent with the EMSA results. The promoter missing the ?332 to ?313 element was not induced by low water activity stress during SSC.  相似文献   
70.
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