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   52篇
  免费   2篇
  国内免费   3篇
系统科学   8篇
现状及发展   17篇
研究方法   3篇
综合类   26篇
自然研究   3篇
  2021年   2篇
  2020年   4篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   4篇
  2014年   4篇
  2013年   2篇
  2012年   5篇
  2011年   3篇
  2010年   1篇
  2006年   2篇
  2005年   2篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  2000年   2篇
  1992年   1篇
  1989年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1973年   4篇
  1972年   1篇
  1966年   1篇
排序方式: 共有57条查询结果,搜索用时 15 毫秒
51.
RNA interference in adult mice   总被引:203,自引:0,他引:203  
McCaffrey AP  Meuse L  Pham TT  Conklin DS  Hannon GJ  Kay MA 《Nature》2002,418(6893):38-39
RNA interference is an evolutionarily conserved surveillance mechanism that responds to double-stranded RNA by sequence-specific silencing of homologous genes. Here we show that transgene expression can be suppressed in adult mice by synthetic small interfering RNAs and by small-hairpin RNAs transcribed in vivo from DNA templates. We also show the therapeutic potential of this technique by demonstrating effective targeting of a sequence from hepatitis C virus by RNA interference in vivo.  相似文献   
52.
53.
54.
H Groux  S Huet  H Valentin  D Pham  A Bernard 《Nature》1989,339(6220):152-154
Integrins are a superfamily of related molecules whose function, where known, is to mediate adhesion. The so-called very-late-activation antigen (VLA) family includes at least five distinct heterodimers, each composed of a unique alpha-subunit non-covalently associated with a common beta-subunit. Several members of the family have been shown to bind extracellular matrix proteins, but the function of VLA-4 is so far unknown. VLA-4 is the only member of the family detected on thymocytes and resting T cells. We show here that an antibody which recognizes the beta-subunit of VLA-4 (CD29) on T cells can inhibit CD4+ cell proliferation triggered by CD2 or CD3, and that binding of this antibody to activated T cells leads to an increase in cyclic AMP levels which is comparable to that elicited by forskolin. These negative signalling effects are unique to this antibody: other CD29 antibodies do not affect the growth of activated CD4 cells but enhance the proliferation of whole T cell populations and abrogate the suppressive effects of mitomycin-treated CD8 cells on CD4-cell growth. Taken together, our results indicate that VLA-4 functions in cell-cell interactions and that it is the target for the suppressive effects of CD8 cells on CD4 cells.  相似文献   
55.
In the isolated Rabbit heart, high pressure, on the one hand, inhibits the noradrenaline release, and on the other hand, induces both the biosynthesis and release of PGs(PGE2,PGF2 alpha) from the auricles and mainly from the right auricle i.e. where the sympathetic nerve endings are the most numerous. Therefore, high pressure, by a negative feedback process, plays a great part in moderating the adrenergic neurotransmission responsible for the hypertension. These effects result from a supplementary pressure which acts on the walls of coronary arteries and arterioles and modifies their distensibility. It thus appears that in the walls of arteries and arterioles there are baroreceptors which are sensitive to the pressure variations in order to regulate adrenergic neurotransmission, by means of a reflex path still unknown.  相似文献   
56.
Four activated carbon(AC) samples prepared from rice husk under different activation temperatures have been characterized by N2adsorption–desorption isotherms, thermogravimetric analysis(TGA–DTA), Fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM). The specific surface area of AC sample reached 2681 m2 g 1under activation temperature of 800 1C. The AC samples were then tested as electrode material; the specific capacitance of the as-prepared activated carbon electrode was found to be 172.3 F g 1using cyclic voltammetry at a scan rate of 5 mV s 1and 198.4 F g 1at current density 1000 mA g 1in the charge/discharge mode.& 2014 Chinese Materials Research Society. Production and hosting by Elsevier B.V. All rights reserved.  相似文献   
57.
Hypovolemic shock (dengue shock syndrome (DSS)) is the most common life-threatening complication of dengue. We conducted a genome-wide association study of 2,008 pediatric cases treated for DSS and 2,018 controls from Vietnam. Replication of the most significantly associated markers was carried out in an independent Vietnamese sample of 1,737 cases and 2,934 controls. SNPs at two loci showed genome-wide significant association with DSS. We identified a susceptibility locus at MICB (major histocompatibility complex (MHC) class I polypeptide-related sequence B), which was within the broad MHC region on chromosome 6 but outside the class I and class II HLA loci (rs3132468, P(meta) = 4.41 × 10(-11), per-allele odds ratio (OR) = 1.34 (95% confidence interval: 1.23-1.46)). We identified associated variants within PLCE1 (phospholipase C, epsilon 1) on chromosome 10 (rs3765524, P(meta) = 3.08 × 10(-10), per-allele OR = 0.80 (95% confidence interval: 0.75-0.86)). We identify two loci associated with susceptibility to DSS in people with dengue, suggesting possible mechanisms for this severe complication of dengue.  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