全文获取类型
收费全文 | 165篇 |
免费 | 0篇 |
专业分类
现状及发展 | 16篇 |
研究方法 | 7篇 |
综合类 | 142篇 |
出版年
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.
Baur JA Pearson KJ Price NL Jamieson HA Lerin C Kalra A Prabhu VV Allard JS Lopez-Lluch G Lewis K Pistell PJ Poosala S Becker KG Boss O Gwinn D Wang M Ramaswamy S Fishbein KW Spencer RG Lakatta EG Le Couteur D Shaw RJ Navas P Puigserver P Ingram DK de Cabo R Sinclair DA 《Nature》2006,444(7117):337-342
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.
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.
148.
Wood V Gwilliam R Rajandream MA Lyne M Lyne R Stewart A Sgouros J Peat N Hayles J Baker S Basham D Bowman S Brooks K Brown D Brown S Chillingworth T Churcher C Collins M Connor R Cronin A Davis P Feltwell T Fraser A Gentles S Goble A Hamlin N Harris D Hidalgo J Hodgson G Holroyd S Hornsby T Howarth S Huckle EJ Hunt S Jagels K James K Jones L Jones M Leather S McDonald S McLean J Mooney P Moule S Mungall K Murphy L Niblett D Odell C Oliver K O'Neil S Pearson D Quail MA Rabbinowitsch E 《Nature》2002,415(6874):871-880
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.