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   414篇
  免费   17篇
电工技术   4篇
综合类   1篇
化学工业   156篇
金属工艺   5篇
机械仪表   3篇
建筑科学   10篇
矿业工程   5篇
能源动力   5篇
轻工业   36篇
水利工程   1篇
无线电   14篇
一般工业技术   77篇
冶金工业   92篇
原子能技术   2篇
自动化技术   20篇
  2021年   6篇
  2020年   13篇
  2019年   3篇
  2018年   11篇
  2017年   9篇
  2016年   12篇
  2015年   7篇
  2014年   15篇
  2013年   25篇
  2012年   15篇
  2011年   21篇
  2010年   19篇
  2009年   10篇
  2008年   17篇
  2007年   11篇
  2006年   9篇
  2005年   3篇
  2004年   5篇
  2003年   6篇
  2002年   7篇
  2001年   13篇
  2000年   10篇
  1999年   3篇
  1998年   32篇
  1997年   23篇
  1996年   10篇
  1995年   10篇
  1994年   9篇
  1993年   8篇
  1992年   2篇
  1991年   7篇
  1990年   4篇
  1989年   6篇
  1988年   2篇
  1987年   6篇
  1986年   2篇
  1985年   5篇
  1984年   10篇
  1983年   2篇
  1981年   6篇
  1980年   2篇
  1976年   3篇
  1975年   2篇
  1973年   5篇
  1971年   2篇
  1941年   2篇
  1940年   6篇
  1939年   1篇
  1938年   2篇
  1937年   1篇
排序方式: 共有431条查询结果,搜索用时 14 毫秒
41.
42.
43.
Attributable risks (ARs) for bladder cancer were computed in relationship to cigarette smoking, coffee consumption, low intake of vegetables, history of cystitis, and occupation using data from a case-control study conducted in northern Italy between 1985 and 1993. Cases were 431 patients with histologically confirmed bladder cancer, and controls were 491 patients admitted to the same network of hospitals for acute, nonneoplastic, and non-urinary-tract diseases. Overall, the AR estimates were 49% for cigarette smoking, 23% for coffee consumption, 16% for low intake of vegetables, 12% for history of cystitis, and 4% for occupation. These five factors together explained more than 70% of bladder cancer cases in this population. The AR for cigarette smoking was significantly higher among men (56%) than women (17%), whereas coffee consumption, low vegetable intake, and cystitis were more important (but not significantly so) among women. These results suggest that more than 2500 of the 5400 deaths due to bladder cancer in Italy in 1990 could have been prevented by the elimination of cigarette smoking. With some appropriate dietary modification and intervention to prevent urinary tract infections and occupational exposures, this figure could approach 4000 avoidable deaths. Thus, bladder cancer could become a rare cause of death in this population.  相似文献   
44.
45.
46.
Cardiac cellular hypertrophy plays an important role in cardiovascular diseases. Up until now, little has been known about the regulation of cellular growth on the level of intracellular signalling. Here, the implication of the p70(S6)-kinase (p70(S6K)) in the hypertrophic response after beta-adrenergic stimulation of cardiac myocytes from adult rats was investigated. Isoproterenol stimulation can activate p70(S6K) in adult cardiomyocytes analysed by direct kinase assays and retarded gel mobility. This signalling of beta-adrenoceptor stimulation is found only under conditions where the cardiomyocytes exhibit also a hypertrophic response to beta-adrenoceptor stimulation as measured by increase in protein content, RNA content and incorporation of radiolabelled amino acids. Rapamycin, a specific inhibitor of this kinase, reduces the trophic responses to control levels, suggesting an involvement of the p70(S6)-kinase in the development of cellular hypertrophy. An engagement of the MAP-kinase (ERK-1/2) pathway in the beta-adrenergic induced growth of cardiac myocytes from adult rats was excluded.  相似文献   
47.
48.
Information on corneal manifestation in pseudoexfoliation syndrome is restricted to specular microscopic studies. We investigated morphologic changes of the posterior cornea of two corneal buttons with Fuchs' endothelial dystrophy obtained at penetrating keratoplasty and of one enucleated glaucomatous eye from three patients with ocular pseudoexfoliation syndrome. By transmission electron microscopy, large clumps of typical pseudoexfoliation material were found adhering to the corneal endothelium and masses of pseudoexfoliation material were incorporated into the posterior Descemet's membrane. In the affected areas, the endothelial layer appeared irregular and discontinuous, with loosely adherent, degenerating cells producing pseudoexfoliation fibers and fibroblastic cells spreading to cover denuded Descemet's membrane. The present findings indicate that the pseudoexfoliation material is initially formed by degenerative endothelial cells and that it becomes subsequently buried by overgrowing cells. The corneal endothelial involvement may potentiate complications of cataract surgery and open angle glaucoma in patients with pseudoexfoliation syndrome.  相似文献   
49.
50.
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