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   165篇
  免费   0篇
现状及发展   16篇
研究方法   7篇
综合类   142篇
  2016年   1篇
  2012年   5篇
  2011年   2篇
  2008年   11篇
  2007年   8篇
  2006年   20篇
  2005年   7篇
  2004年   24篇
  2003年   16篇
  2002年   11篇
  2001年   8篇
  2000年   5篇
  1999年   1篇
  1993年   1篇
  1987年   2篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1979年   5篇
  1978年   3篇
  1977年   1篇
  1975年   2篇
  1974年   1篇
  1972年   1篇
  1971年   4篇
  1970年   4篇
  1969年   4篇
  1968年   2篇
  1967年   9篇
  1965年   1篇
  1955年   1篇
排序方式: 共有165条查询结果,搜索用时 93 毫秒
141.
142.
Resveratrol improves health and survival of mice on a high-calorie diet   总被引:3,自引:0,他引:3  
Resveratrol (3,5,4'-trihydroxystilbene) extends the lifespan of diverse species including Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster. In these organisms, lifespan extension is dependent on Sir2, a conserved deacetylase proposed to underlie the beneficial effects of caloric restriction. Here we show that resveratrol shifts the physiology of middle-aged mice on a high-calorie diet towards that of mice on a standard diet and significantly increases their survival. Resveratrol produces changes associated with longer lifespan, including increased insulin sensitivity, reduced insulin-like growth factor-1 (IGF-I) levels, increased AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha) activity, increased mitochondrial number, and improved motor function. Parametric analysis of gene set enrichment revealed that resveratrol opposed the effects of the high-calorie diet in 144 out of 153 significantly altered pathways. These data show that improving general health in mammals using small molecules is an attainable goal, and point to new approaches for treating obesity-related disorders and diseases of ageing.  相似文献   
143.
144.
R H Pearson  I Pascher 《Nature》1979,281(5731):499-501
Lecithin is a major structural component of biological membranes. Because of their amphipathic nature, lecithin and related phospholipids tend to aggregate as bilayer structures in which the hydrophilic head groups are orientated towards the surface and the hydrophobic hydrocarbon chains towards the interior. A detailed knowledge of the three-dimensional structure of lecithins will aid in the understanding of their role in membrane structure and function, but is still lacking. To this end we have now crystallised and solved the molecular structure of 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine (DMPC), a lecithin species in the naturally occurring configuration. This compound crystallises from a water-containing solution, with two water molecules (5% w/w) of hydration.  相似文献   
145.
146.
147.
Pearson H 《Nature》2002,418(6893):14-15
  相似文献   
148.
We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.  相似文献   
149.
150.
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