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   2765篇
  免费   0篇
电工技术   1篇
化学工业   13篇
建筑科学   1篇
轻工业   3篇
石油天然气   2篇
无线电   3篇
一般工业技术   4篇
冶金工业   2734篇
自动化技术   4篇
  2018年   1篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2008年   2篇
  2007年   2篇
  2006年   1篇
  2004年   1篇
  2003年   3篇
  2000年   2篇
  1999年   80篇
  1998年   799篇
  1997年   434篇
  1996年   305篇
  1995年   165篇
  1994年   150篇
  1993年   168篇
  1992年   16篇
  1991年   34篇
  1990年   34篇
  1989年   37篇
  1988年   43篇
  1987年   39篇
  1986年   27篇
  1985年   32篇
  1984年   1篇
  1983年   3篇
  1982年   15篇
  1981年   14篇
  1980年   31篇
  1978年   8篇
  1977年   94篇
  1976年   212篇
  1975年   5篇
  1955年   4篇
排序方式: 共有2765条查询结果,搜索用时 15 毫秒
41.
42.
43.
Autopsies of two patients with onchocerciasis in the Republic of Za?re are reported. In one patient elephantiasis who died following diethylcarbamazine therapy there were large numbers of microfilariae of Onchocerca volvulus in the kidney, liver, pancreas, and lung. In the second patient, who also had leprosy and hyperinfection strongyloidiasis, we found an encapsulated adult O. volvulus in the wall of the thoracic aorta.  相似文献   
44.
45.
Renal lymph and systemic (posterior) lymph were studied in hydropenic rats. As a consequence of the anatomical arrangement of collecting lymphatics near the kidney, mixed renal and systemic lymph tributaries are situated in such a way that sampling pure renal lymph is difficult. Pure renal lymph contains 1.0 +/- 0.1 g/100 ml total protein with an albumin-to-globulin (A/G) ratio of 2.1 +/- 0.1. Mixed renal and extrarenal lymphatic tributaries contain 3.3 +/- 0.2 g/100 ml total protein with an A/G ratio of 1.8 +/- 0.2. Corresponding values in the plasma are 4.9 +/- 0.2 and 1.2 +/- 0.1 g/100 ml, respectively. Previous studies in which the concentration of renal lymph protein was determined as 30-50% of that in plasma were probably in error due to contamination of renal samples by posterior lymph ducts. The amount of systemic and renal lymph mixing is highly variable from one animal to another. Our renal lymph samples in carefully controlled and prepared Munich-Wistar rats contained a total protein uniformly 20% of that in plasma.  相似文献   
46.
Clinical and morphologic observations are described in a 46 year old woman with fatal trichinosis. Attention is called to the occurrence of extensive ventricular endocardial damage with superimposed thrombosis; Evidence is presented to indicate that the most likely cause of the endocardial damage is the associated eosinophilia. The mechanism by which eosinophils damage endocardium, however, remains obscure.  相似文献   
47.
48.
We have determined the nucleotide sequence of the blaS gene encoding the carbapenem-hydrolyzing L-1 beta-lactamase from Stenotrophomonas maltophilia GN12873. Analysis of the DNA and deduced amino acid sequences identified a product of 290 amino acids. Comparisons of the L-1 amino acid sequence with those of other zinc beta-lactamases showed 88.6% identity with the L-1 enzyme from S. maltophilia IID1275 and less than 20% identity with other class B metalloenzymes.  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