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   2807篇
  免费   211篇
  2022年   23篇
  2021年   33篇
  2020年   19篇
  2019年   26篇
  2018年   37篇
  2017年   33篇
  2016年   68篇
  2015年   85篇
  2014年   104篇
  2013年   135篇
  2012年   161篇
  2011年   152篇
  2010年   100篇
  2009年   92篇
  2008年   153篇
  2007年   148篇
  2006年   124篇
  2005年   134篇
  2004年   106篇
  2003年   120篇
  2002年   114篇
  2001年   77篇
  2000年   68篇
  1999年   58篇
  1998年   49篇
  1997年   36篇
  1996年   31篇
  1995年   34篇
  1994年   24篇
  1993年   37篇
  1992年   65篇
  1991年   36篇
  1990年   31篇
  1989年   31篇
  1988年   38篇
  1987年   27篇
  1986年   23篇
  1985年   31篇
  1984年   32篇
  1983年   22篇
  1981年   24篇
  1980年   23篇
  1979年   30篇
  1978年   19篇
  1977年   21篇
  1975年   18篇
  1974年   15篇
  1973年   16篇
  1972年   20篇
  1970年   18篇
排序方式: 共有3018条查询结果,搜索用时 31 毫秒
1.
Recently, we have shown that inhalation of hydrogen sulfide (H2S) protects against ventilator-induced lung injury (VILI). In the present study, we aimed to determine the underlying molecular mechanisms of H2S-dependent lung protection by analyzing gene expression profiles in mice. C57BL/6 mice were subjected to spontaneous breathing or mechanical ventilation in the absence or presence of H2S (80 parts per million). Gene expression profiles were determined by microarray, sqRT-PCR and Western Blot analyses. The association of Atf3 in protection against VILI was confirmed with a Vivo-Morpholino knockout model. Mechanical ventilation caused a significant lung inflammation and damage that was prevented in the presence of H2S. Mechanical ventilation favoured the expression of genes involved in inflammation, leukocyte activation and chemotaxis. In contrast, ventilation with H2S activated genes involved in extracellular matrix remodelling, angiogenesis, inhibition of apoptosis, and inflammation. Amongst others, H2S administration induced Atf3, an anti-inflammatory and anti-apoptotic regulator. Morpholino mediated reduction of Atf3 resulted in elevated lung injury despite the presence of H2S. In conclusion, lung protection by H2S during mechanical ventilation is associated with down-regulation of genes related to oxidative stress and inflammation and up-regulation of anti-apoptotic and anti-inflammatory genes. Here we show that Atf3 is clearly involved in H2S mediated protection.  相似文献   
2.
Summary On adapting brackish waterAnguilla anguilla to fresh water it was noted that, while the plasma sodium, magnesium,pCO2 and pH were held reasonably constant, there was a substantial fall in chloride concentration (–33 mEq). The gradient of the linear correlations between plasma sodium and chloride also fell (brackish water gradient=0.92, fresh water gradient=0.21) indicating that a new pattern of plasma ion interrelationships was being established. Comparison with plasma Na/Cl ion ratios from other fishes suggested that this phenomenon was peculiar toA. anguilla. Corresponding with the very low plasma chloride levels plasma bicarbonate was four to five times that found in other fishes, and this was thought related to the finding that the haematocrit value almost doubled during adaptation to fresh water. In fresh water adapted fish a fall in plasma chloride was associated with a rise in plasma bicarbonate, however the charge compensation effect of this response was only partial as summing the common plasma cations and anions left an anion deficit of about 34 mEq to be accounted for.  相似文献   
3.
4.
5.
A maize acetyl-coenzyme A carboxylase cDNA sequence.   总被引:5,自引:0,他引:5       下载免费PDF全文
  相似文献   
6.
7.
8.
9.
Cephalometric measurements on 50 English and 50 Indian adults, equally divided as regards sex, were compared for sex and group difference. Evaluation of the average measurements indicated that the female facial size was generally smaller than the male: the Indian face was not prognathic but was smaller and had smaller facial and gonial angles, and the lower incisor was proclined as compared with the English face. A statistical analysis using the Generalized T2-test and Discriminatory Analysis brought out these differences very convincingly, and with nearly 80% accuracy it was possible to classify the individuals to their correct sex and Indian or English group. Incidentally it was found that the Sella Nasion Plane, Maxillary Plane and Frankfort Plane are all equally suitable for assessing the upper incisor inclination.  相似文献   
10.
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