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   352435篇
  免费   27675篇
  国内免费   17369篇
电工技术   21402篇
技术理论   58篇
综合类   44255篇
化学工业   44603篇
金属工艺   11450篇
机械仪表   16710篇
建筑科学   50386篇
矿业工程   19857篇
能源动力   13062篇
轻工业   19938篇
水利工程   29480篇
石油天然气   19040篇
武器工业   2805篇
无线电   19763篇
一般工业技术   23257篇
冶金工业   19029篇
原子能技术   4029篇
自动化技术   38355篇
  2024年   1099篇
  2023年   3499篇
  2022年   6787篇
  2021年   8214篇
  2020年   8820篇
  2019年   7356篇
  2018年   6979篇
  2017年   8632篇
  2016年   10046篇
  2015年   10863篇
  2014年   20099篇
  2013年   19003篇
  2012年   24068篇
  2011年   25240篇
  2010年   19728篇
  2009年   20569篇
  2008年   18952篇
  2007年   24768篇
  2006年   23358篇
  2005年   20627篇
  2004年   17290篇
  2003年   15652篇
  2002年   13058篇
  2001年   10921篇
  2000年   9241篇
  1999年   7462篇
  1998年   5578篇
  1997年   4818篇
  1996年   4300篇
  1995年   3694篇
  1994年   3212篇
  1993年   2399篇
  1992年   2112篇
  1991年   1571篇
  1990年   1345篇
  1989年   1218篇
  1988年   951篇
  1987年   687篇
  1986年   527篇
  1985年   452篇
  1984年   425篇
  1983年   296篇
  1982年   247篇
  1981年   181篇
  1980年   149篇
  1979年   131篇
  1978年   69篇
  1977年   82篇
  1976年   63篇
  1975年   59篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
为进一步开发国际钢材市场,研制开发了符合加拿大可焊性高强度钢筋标准要求的高强度钢筋.制定了化学成分及力学性能内控标准,分析了生产工艺各环节对成分和性能的影响,依据试验结果,在全面统计分析的基础上,调整了冶炼成分,生产的531批钢筋全部合格.通过直方图及回归分析,说明了制定的产品生产工艺可行,也为今后的生产提供了理论依据。  相似文献   
152.
黄玲 《冶金动力》2003,(6):49-51
通过高炉鼓风机扩压叶片断裂事故,从化学分析、物理检验,结合使用情况对扩压叶片断裂原因进行了详细分析,并提出了改进措施。  相似文献   
153.
分析了高温复合固硫剂各成分的作用,实验研究了在不同配比的燃烧试验下,各成分对燃煤着火和燃烧以及对炉渣固硫的影响,得出了该煤种高温复合固硫剂的最佳配方。  相似文献   
154.
155.
在分析工程招投标中的违法现象及产生原因的基础上,提出相应对策和减少违法投标的措施。  相似文献   
156.
The 2004 Gold Medal Award for Life Achievement in the Application of Psychology was awarded to Edwin A. Fleishman, for his significant contributions to the science and applications of psychology, which he has sustained over his remarkable career. He is cited for his research, which has had a profound influence on our understanding of human capabilities, their measurement, their development, and their application in the world of work. Through his many influential leadership roles, as president of the International Association of Applied Psychology and three divisions of the American Psychological Association, and as editor of the Journal of Applied Psychology, he has helped shape our profession. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
157.
Fodor and Pylyshyn (1988) have argued that the cognitive architecture is not Connectionist. Their argument takes the following form: (1) the cognitive architecture is Classical; (2) Classicalism and Connectionism are incompatible; (3) therefore the cognitive architecture is not Connectionist. In this essay I argue that Fodor and Pylyshyn's defenses of (1) and (2) are inadequate. Their argument for (1), based on their claim that Classicalism best explains the systematicity of cognitive capacities, is an invalid instance of inference to the best explanation. And their argument for (2) turns out to be question-begging. The upshot is that, while Fodor and Pylyshyn have presented Connectionists with the important empirical challenge of explaining systematicity, they have failed to provide sufficient reason for inferring that the cognitive architecture is Classical and not Connectionist.  相似文献   
158.
It is necessary to determine the accurate reflectance of painted surfaces for the review of paint finishes by computer graphics (CG) before actual painting of the exterior color of automobiles, and for quality control during production and inspection processes. We have optimized a method for measuring reflectance by using a statistical technique. We have found that the reflectance of a painted surface is best measured at an incident angle of 60° and at five aspecular angles of 10°, 18°, 28°, 40°, and 90°. Our method makes it possible to accurately reproduce reflection characteristics of paint finishes containing special flake pigments, such as pearl mica. Also it was proved that our method can apply not only to solid and metallic coatings but to all painted surfaces. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 275–282, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20125  相似文献   
159.
This article theoretically investigates the drying of uncoated paper with gas-fired infrared (IR) emitters installed within the drying section of a given commercial paper machine. Specifically, it presents the ideal location of two opposing IR emitters within the drying section. The ideal location of the two opposing IR emitters corresponds to the highest machine speed with specified average moisture content of paper sheet at the end of the drying section. This article also presents the average evaporation rate, temperature, and moisture content of the paper sheet as it travels through the drying section with the two opposing IR emitters operating at the optimum location. In addition, the temperature and moisture profiles in the sheet thickness direction, before and after the IR emitters, are provided. This article is not concerned with the potential effects of drying with IR emitters on paper sheet properties and machine runnability issues.  相似文献   
160.
This study examines the links between antecedents and consequences of Gabonese teachers' (N= 152) work motivation. The theoretical underpinnings are based on the Motivational Model of Job Burnout (MMJB) which is grounded in Self-Determination Theory (SDT) and states that the more supervisors satisfy an employee's need for self-determination, competence, and relatedness, the more self-determined is the latter's work motivation. The level of self-determined motivation has an impact on job satisfaction, which in turn determines life satisfaction. Higher levels of self-determined motivation also buffer emotional exhaustion and psychological distress. The model was confirmed via structural equation modeling and provides support for the validity and generalizability of the MMJB and SDT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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