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   249篇
  免费   25篇
  2023年   1篇
  2021年   5篇
  2020年   1篇
  2019年   2篇
  2017年   5篇
  2016年   6篇
  2015年   15篇
  2014年   8篇
  2013年   15篇
  2012年   15篇
  2011年   9篇
  2010年   16篇
  2009年   6篇
  2008年   19篇
  2007年   21篇
  2006年   11篇
  2005年   10篇
  2004年   13篇
  2003年   13篇
  2002年   7篇
  2001年   5篇
  2000年   5篇
  1999年   10篇
  1998年   6篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   6篇
  1985年   1篇
  1984年   3篇
  1982年   3篇
  1981年   3篇
  1979年   1篇
  1978年   2篇
  1974年   2篇
  1973年   1篇
  1969年   1篇
  1968年   1篇
  1965年   1篇
  1963年   1篇
  1961年   1篇
排序方式: 共有274条查询结果,搜索用时 15 毫秒
1.
2.
Summary The reductive cleavage of the aclacinomycins A (I), Y (II), and B (III) by intact mycelia or subcellular fractions of the producer strain S. spec. AM 33352/F43 is suppressed in the presence of uncouplers, complex-forming agents, detergents, and some metal anions such as chromate. Increased concentration of the latter in complete cultures caused rearrangement of I to III.  相似文献   
3.
This paper describes differences in response in seventeen patients with essential hypertension who participated in a treatment program consisting of electromyograph biofeedback assisted relaxation training. Responders were found to have higher treatment values of urinary and plasma cortisol, Trait Anxiety and forehead muscle tension compared to treatment failures. Responders also sustained greater decreases in plasma, and urinary cortisol after treatment. These data are discussed in light of the ability to predict which hypertensive patients may be most benefitted by a relaxation based treatment.We would like to thank Dr. Charles Spielberger for his permission to use the State-Trait Anxiety Inventory. We thank Michael Robinson for assistance with statistical analysis.  相似文献   
4.
5.
6.
During the last decade new anthracycline-type structures with potential usefulness in cancer treatment have been supplied both by new microbial strains and by bioconversions of precursor molecules employing cells or enzymes. We highlight recent advances in bioconversion of anthracycline structures with the main focus on late transformations such as are carried out by oxidoreductases.  相似文献   
7.
Interaction of metabolic inhibitors with actin fibrils   总被引:3,自引:0,他引:3  
Summary The dependence of the arrangement of fibrillar actin in cultured endothelial cells on metabolic conditions was investigated with cellular elements derived from the heart of Xenopus laevis tadpoles. Either primary culture or an established cell line (XTH-2) were used in these studies The metabolic stage of the cells was influenced by inhibiting respiration and lactate production. The actin pattern was revealed either by indirect immunofluorescence or by tetramethylrhodaminyl (TRITC)-phalloidin fluorescence. Total block of energy supply causes in all cases a distinct loss of actin fibrils, while inhibition of respiration alone increases the variability of actin organization. In primary XTH cells but not in XTH-2 cells cyanide disintegrates most of the actin fibres during 3 h of treatment. This effect is independent of the inhibition of respiration, since actin gels prepared from skeletal muscle also undergo destruction in the presence of cyanide. It is concluded that the actin fibrils of the primary cells and the established line behave differently to changing metabolic conditions and to application of KCN.  相似文献   
8.
Schriftenschau     
Ohne Zusammenfassung  相似文献   
9.
Aging leads to a progressive functional decline of the immune system, rendering the elderly increasingly susceptible to disease and infection. The degree to which immune cell senescence contributes to this decline remains unclear, however, since markers that label immune cells with classical features of cellular senescence accurately and comprehensively have not been identified. Using a second‐generation fluorogenic substrate for β‐galactosidase and multi‐parameter flow cytometry, we demonstrate here that peripheral blood mononuclear cells (PBMCs) isolated from healthy humans increasingly display cells with high senescence‐associated β‐galactosidase (SA‐βGal) activity with advancing donor age. The greatest age‐associated increases were observed in CD8+ T‐cell populations, in which the fraction of cells with high SA‐βGal activity reached average levels of 64% in donors in their 60s. CD8+ T cells with high SA‐βGal activity, but not those with low SA‐βGal activity, were found to exhibit features of telomere dysfunction‐induced senescence and p16‐mediated senescence, were impaired in their ability to proliferate, developed in various T‐cell differentiation states, and had a gene expression signature consistent with the senescence state previously observed in human fibroblasts. Based on these results, we propose that senescent CD8+ T cells with classical features of cellular senescence accumulate to levels that are significantly higher than previously reported and additionally provide a simple yet robust method for the isolation and characterization of senescent CD8+ T cells with predictive potential for biological age.  相似文献   
10.
Telomere integrity is critical for telomere function and genomic stability. We previously demonstrated that non-erythroid α-spectrin (αIISp) is present in mammalian cell nuclei where it is important in repair of DNA interstrand cross-links (ICLs) and chromosome stability. We now demonstrate that αIISp is also important for telomere maintenance after ICL damage. It localizes to telomeres in S phase after ICL damage where it has enhanced association with TRF1 and TRF2 and is required for recruitment of the ICL repair protein, XPF, to damage-induced foci at telomeres. In telomerase-positive normal cells depleted of αIISp by siRNA or in Fanconi anemia, complementation group A (FA-A) cells, where αIISp levels are 35–40% of normal, ICL damage results in failure of XPF to localize to telomeres, markedly increased telomere dysfunction-induced foci, followed by catastrophic loss of telomeres. Restoration of αIISp levels to normal in FA-A cells corrects these deficiencies. Our studies demonstrate that αIISp is critical for repair of DNA ICLs at telomeres, likely by facilitating the recruitment of repair proteins similar, but not identical, to its proposed role in repair of DNA ICLs in genomic DNA and that this function in turn is critical for telomere maintenance after DNA ICL damage.  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