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   1267篇
  免费   1篇
化学工业   3篇
金属工艺   2篇
机械仪表   2篇
轻工业   15篇
水利工程   1篇
一般工业技术   3篇
冶金工业   1241篇
自动化技术   1篇
  2021年   1篇
  2015年   1篇
  2014年   1篇
  2012年   1篇
  2011年   3篇
  2010年   2篇
  2009年   3篇
  2006年   1篇
  2005年   1篇
  2004年   4篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1999年   47篇
  1998年   394篇
  1997年   203篇
  1996年   153篇
  1995年   65篇
  1994年   48篇
  1993年   61篇
  1992年   11篇
  1991年   15篇
  1990年   10篇
  1989年   16篇
  1988年   15篇
  1987年   12篇
  1986年   8篇
  1985年   5篇
  1984年   1篇
  1983年   3篇
  1982年   5篇
  1981年   11篇
  1980年   7篇
  1978年   5篇
  1977年   35篇
  1976年   111篇
  1975年   2篇
  1955年   2篇
排序方式: 共有1268条查询结果,搜索用时 0 毫秒
121.
122.
We report the case of a 26-year-old man with diffuse esophageal leiomyomatosis involving the trachea. The tumor was resected by total esophagectomy and partial resection of the trachea and the left main bronchus. The tracheobronchial defect was repaired with a free forearm skin graft with satisfactory outcome. This approach offers good long-term prospects.  相似文献   
123.
Hemangiomas are the most common benign vascular tumor found in the liver. In this study, 103 cases of hepatic hemangiomas were analysed in a retrospective manner. Image aspects such as those seen in ultrassonography, computed tomography, nuclear magnetic resonance and arteriography are discussed. The incidence was higher amongst the female sex, between individuals from 40 to 60 years old, which presented predominantly without symptoms (66%) and localized mainly in the right hepatic lobe (74%). The meaning of those aspects, when adopted, permits the clinicians to differentiate benign from malignant nodular lesions in the liver.  相似文献   
124.
Early pregnancy factor (EPF) has been identified as a homologue of chaperonin 10 (cpn10) with immunosuppressive and growth factor properties. As a homologue of cpn10, it belongs to the heat shock family of proteins (hsp) but, unlike other members of this family, EPF is detected extracellularly. Early pregnancy factor was first discovered in pregnancy serum by the rosette inhibition test, and the novelty of its discovery was that its presence could diagnose pregnancy within 6-24 h of a fertile mating. As well as being a monitor of the presence of a viable embryo, it is necessary for embryonic survival. In this capacity it acts as both an immunosuppressant and growth factor. Early pregnancy factor is also a product of proliferating primary and neoplastic cells and functions as an autocrine growth factor both in vivo and in vitro. It has a modifying effect on the outcome of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. Early pregnancy factor is considered to be one of the major factors involved in the modification of multiple sclerosis observed during pregnancy.  相似文献   
125.
126.
The present study aimed to demonstrate conditioned inhibition of Pavlovian conditioning of autonomic responses in humans. Subjects (N = 21) were presented initially with four geometric shapes (A, B, C and D). An electric shock served as the unconditioned stimulus (US) during acquisition. Conditional stimuli lasted for 8 s and US onset coincided with CS offset. Subjects were trained with A-US, C-US, and AC-US pairings and AB alone and B alone presentations. The subsequent summation test consisted of C-US pairings and CB alone and CD alone presentations. Conditioning was evident in self-reported US expectancy and first and second interval electrodermal responses. Evidence for conditioned inhibition during the summation test was found in US expectancy and second interval electrodermal responses.  相似文献   
127.
128.
Tobacco use is responsible for more deaths in the United States than any other factor. Nurses are in a unique position to convey life-saving messages to clients regarding tobacco use. To gauge the type and extent of tobacco-related background knowledge acquired by nurses in the course of their education, the Nurses' Committee of the Illinois Division of the American Cancer Society (ACS) surveyed 70 nursing programs in the state of Illinois. The number of lecture hours spent on tobacco-related issues was greater in LPN programs than in either associate or baccalaureate degree programs, and instruction was scattered throughout the curriculum of each program. Most schools reported heavy reliance on adult medical-surgical textbooks to convey tobacco-related content. The most recent editions of the textbooks used by the schools were reviewed, and they also were found to adopt a scattered approach, with a disappointing lack of depth regarding the hazards of tobacco. It is recommended a single course be identified as responsible for relaying tobacco-related content and information supplied by general medical-surgical textbooks be supplemented by materials drawn from other sources.  相似文献   
129.
130.
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