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   16484篇
  免费   235篇
  国内免费   22篇
电工技术   187篇
综合类   3篇
化学工业   2001篇
金属工艺   361篇
机械仪表   338篇
建筑科学   512篇
矿业工程   60篇
能源动力   306篇
轻工业   1216篇
水利工程   89篇
石油天然气   118篇
无线电   1508篇
一般工业技术   2336篇
冶金工业   6153篇
原子能技术   159篇
自动化技术   1394篇
  2021年   98篇
  2019年   102篇
  2018年   135篇
  2017年   101篇
  2016年   94篇
  2015年   108篇
  2014年   224篇
  2013年   571篇
  2012年   305篇
  2011年   406篇
  2010年   333篇
  2009年   336篇
  2008年   450篇
  2007年   439篇
  2006年   433篇
  2005年   385篇
  2004年   323篇
  2003年   364篇
  2002年   308篇
  2001年   321篇
  2000年   315篇
  1999年   416篇
  1998年   1772篇
  1997年   1104篇
  1996年   773篇
  1995年   513篇
  1994年   447篇
  1993年   477篇
  1992年   281篇
  1991年   263篇
  1990年   273篇
  1989年   229篇
  1988年   233篇
  1987年   228篇
  1986年   210篇
  1985年   261篇
  1984年   208篇
  1983年   205篇
  1982年   207篇
  1981年   191篇
  1980年   201篇
  1979年   130篇
  1978年   137篇
  1977年   258篇
  1976年   390篇
  1975年   136篇
  1974年   125篇
  1973年   107篇
  1972年   78篇
  1970年   83篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
PURPOSE: To use a controlled, randomized design to assess the effect on patient satisfaction of an intensive psychosocial training program for residents. METHOD: Twenty-six first-year residents, in two internal medicine and family practice community-based programs affiliated with the Michigan State University College of Human Medicine, were randomly assigned during 1991 and 1992 to a control group or a one-month intensive training program. Experiential teaching focused on many psychosocial skills required in primary care. A 29-item questionnaire administered before and after the residents' training evaluated their patients' satisfaction regarding patient disclosure, physician empathy, confidence in physician, general satisfaction, and comparison of the physician with other physicians. Analyses of covariance with groups and gender as factors and pre-training patient satisfaction scores as the covariate evaluated the effect of the training. RESULTS: The patients of the trained residents expressed more confidence in their physicians (p = .01) and more general satisfaction (p = .02) than did the patients of controls. The effect of training on patient satisfaction with patient disclosure (p < .01) and physician empathy (p < .05) was greater for female than for male residents. CONCLUSION: The intensive psychosocial training program for residents improved their patients' satisfaction.  相似文献   
93.
Don C. Smith 《Refocus》2003,4(6):62-63
In addition to having one of the top environmental law programs in the United States, the University of Denver College of Law now has a building that demonstrates the institution ‘practices what it preaches’ when it comes to concern for the environment. Built on the front range of the Colorado Rocky Mountains, the 181,000 square foot, $63 million facility which opened in August will be the first certified “green” law school in the country. Don C. Smith, U.S. Correspondent explains the attributes that distinguish the building from conventional ones.  相似文献   
94.
95.
In a patient wounded by a gunshot in the abdomen, the bullet was radiologically located intradurally at S1 level. Although she had no neurological deficit at admission, she developed pain and motor weakness a few days later. At operation the bullet was found at L4 level and its removal resulted in complete neurological recovery.  相似文献   
96.
L. Berkowitz and E. Harmon-Jones (see record 2004-15096-001) challenge appraisal theories of emotion by describing 2 sets of conditions (physical discomfort and anger-related muscle actions) in which anger appears to be elicited in the absence of theoretically predicted appraisals. In response, the authors discuss the ability of the specific appraisal model they have developed (e.g., C. A. Smith & L. D. Kirby, 2000, 2001; C. A. Smith & R. S. Lazarus, 1990) to account for such instances of anger. First, a number of issues are clarified relevant to the authors' model, including the nature of both the cognitive operations underlying appraisal and the specific appraisals hypothesized to evoke anger. The authors then describe how their model can account for the instances of anger described by L. Berkowitz and E. Harmon-Jones and how both accounts might be tested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
97.
98.
The author discusses the concept that data sampled beyond the Nyquist frequency is meaningless. A simple signal processing scheme to extend resolution to nearly twice the Nyquist without the problem of alias emerged. It starts by placing one-dimensional signals into a simulated sample-and-hold process in a Mathcad application  相似文献   
99.
Advances in instrumentation have made it possible in recent years to study the microstructure of inorganic materials at atomic resolution using the technique of high-resolution electron microscopy (HREM). Details of instrumentation have been described elsewhere [l], and applications and trends for HREM have recently been reviewed [2]. Although HREM is primarily a technique for studying bulk defects, it is increasingly also being applied in the profile-imaging mode to derive information about surfaces [3]. The high spatial resolution of the electron microscope makes it a valuable tool for the characterization of heterogeneous catalysts. This is evidenced by the growing number of studies wherein electron micrographs are being used to describe the morphology of a particular catalyst. Profile imaging is proving particularly useful in this regard for following changes in surface structure as a function of treatment conditions [4].  相似文献   
100.
To examine the separate effects of viscosity and sweetness on astringency, aqueous solutions of grape seed tannin (GST) were thickened with carboxymethyl cellulose (CMC) from 2 to 45 cP (experiment 1) or sweetened with 0 to 1.8 g/L aspartame (experiment 2). Trained subjects continuously rated astringency and bitterness in duplicate. Subjects were categorized by the salivary flow induced by citric acid and ability to taste n-propyl thiouracil (PROP). In experiment 1, maximum intensity and total duration of astringency were significantly decreased as viscosity rose, although time to maximum intensity of astringency was not affected. Maximum intensity and total duration of bitterness were not significantly affected by increasing viscosity; however, the onset of bitterness was significantly delayed. In experiment 2, increasing sweetness had no affect on any astringency parameter, although maximum intensity of bitterness was significantly decreased. Neither PROP nor salivary flow-status had any effect on perception of bitterness or astringency in either experiment.  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