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   2237篇
  免费   0篇
综合类   1篇
化学工业   14篇
金属工艺   4篇
机械仪表   1篇
建筑科学   1篇
能源动力   4篇
轻工业   4篇
石油天然气   1篇
无线电   4篇
一般工业技术   5篇
冶金工业   2194篇
自动化技术   4篇
  2019年   1篇
  2015年   1篇
  2013年   1篇
  2012年   1篇
  2011年   3篇
  2010年   1篇
  2009年   5篇
  2008年   1篇
  2007年   3篇
  2006年   4篇
  2004年   1篇
  2003年   8篇
  2002年   1篇
  2001年   2篇
  2000年   2篇
  1999年   78篇
  1998年   646篇
  1997年   403篇
  1996年   228篇
  1995年   139篇
  1994年   116篇
  1993年   123篇
  1992年   33篇
  1991年   43篇
  1990年   27篇
  1989年   37篇
  1988年   28篇
  1987年   30篇
  1986年   17篇
  1985年   19篇
  1984年   2篇
  1983年   7篇
  1982年   10篇
  1981年   12篇
  1980年   19篇
  1979年   2篇
  1978年   7篇
  1977年   60篇
  1976年   110篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1968年   2篇
  1955年   1篇
排序方式: 共有2237条查询结果,搜索用时 15 毫秒
101.
102.
Tested the hypothesis that the procedures used by leaders to allocate outcomes have an impact on leadership evaluations that is independent of outcome level or outcome fairness. Two studies tested this hypothesis within the context of 132 college students' evaluations of teachers, and two tested it within the context of citizen evaluations of political leaders; Ss in the latter 2 studies were 50 residents of a university town and 156 undergraduates. The procedural justice hypothesis was strongly supported by all 4 studies. In each, strong procedural influences on evaluation were found, influences that were independent of outcome level or outcome fairness. In addition, in both surveys of naturally occurring evaluations, variations in procedural fairness had a much greater impact on leadership endorsement than did variations in outcome level, outcome satisfaction, or outcome fairness. Findings suggest that in experimental settings, Ss can be sensitive to both outcomes and procedures. In natural settings, however, individuals focus on procedures rather than outcomes in forming their evaluations of leaders. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
103.
104.
105.
Phasic changes in cardiac reactivity to innocuous stimuli, presented in a sensory disparity paradigm, were used to evaluate habituation and learning processes in five decerebrate subjects. Three subjects showed systematic changes over trials in the pattern of cardiac response to simple auditory or visual stimuli, indicative of habituation. In addition, tests for associative learning were given after repeated presentations of two paired stimuli. The appearance of a marked cardiac orienting response, to the unpredictable omission of the second stimulus, documented the development of a conditioned association in these same three subjects. One additional subject failed to show a consistent pattern of response to the stimuli, and another demonstrated a consistent response which was not subject to habituation. Overall, these findings support the view that learning processes are not solely the product of the cerebral hemispheres, but reflect general integrative features of the human neuraxis.  相似文献   
106.
107.
108.
109.
Rapid Manufacturing, and specifically Selective Laser Sintering, has the potential to become one of the most useful manufacturing techniques of the future, largely as a result of the extremely high levels of geometric complexity which can be produced. As the use of these technologies becomes more widespread, so the amount, and variety, of materials available for use in these processes also increases. However, the Selective Laser Sintering process can be both expensive and time-consuming when testing new materials. A method of off-line casting has been proposed here, and the tensile properties of parts produced using this method are compared with the properties achieved in Selective Laser Sintered parts produced in the same materials. For the materials tested it has been shown that the casting method provided an acceptable correlation with the properties of the Selective Laser Sintered parts, rendering this a suitable method of assessing the properties of a Selective Laser Sintering material without the requirement to produce a full build.  相似文献   
110.
Mice deficient in the cytokines tumor necrosis factor (TNF) or lymphotoxin (LT) alpha/beta lack polarized B cell follicles in the spleen. Deficiency in CXC chemokine receptor 5 (CXCR5), a receptor for B lymphocyte chemoattractant (BLC), also causes loss of splenic follicles. Here we report that BLC expression by follicular stromal cells is defective in TNF-, TNF receptor 1 (TNFR1)-, LTalpha- and LTbeta-deficient mice. Treatment of adult mice with antagonists of LTalpha1beta2 also leads to decreased BLC expression. These findings indicate that LTalpha1beta2 and TNF have a role upstream of BLC/CXCR5 in the process of follicle formation. In addition to disrupted follicles, LT-deficient animals have disorganized T zones. Expression of the T cell attractant, secondary lymphoid tissue chemokine (SLC), by T zone stromal cells is found to be markedly depressed in LTalpha-, and LTbeta-deficient mice. Expression of the SLC-related chemokine, Epstein Barr virus-induced molecule 1 ligand chemokine (ELC), is also reduced. Exploring the basis for the reduced SLC expression led to identification of further disruptions in T zone stromal cells. Together these findings indicate that LTalpha1beta2 and TNF are required for the development and function of B and T zone stromal cells that make chemokines necessary for lymphocyte compartmentalization in the spleen.  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