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   4251篇
  免费   189篇
  国内免费   5篇
电工技术   21篇
综合类   8篇
化学工业   1039篇
金属工艺   44篇
机械仪表   48篇
建筑科学   186篇
矿业工程   13篇
能源动力   67篇
轻工业   728篇
水利工程   28篇
石油天然气   9篇
无线电   129篇
一般工业技术   489篇
冶金工业   1086篇
原子能技术   29篇
自动化技术   521篇
  2023年   20篇
  2022年   54篇
  2021年   201篇
  2020年   82篇
  2019年   99篇
  2018年   108篇
  2017年   84篇
  2016年   101篇
  2015年   95篇
  2014年   134篇
  2013年   263篇
  2012年   174篇
  2011年   227篇
  2010年   193篇
  2009年   156篇
  2008年   216篇
  2007年   193篇
  2006年   150篇
  2005年   136篇
  2004年   119篇
  2003年   97篇
  2002年   121篇
  2001年   73篇
  2000年   66篇
  1999年   85篇
  1998年   80篇
  1997年   53篇
  1996年   73篇
  1995年   50篇
  1994年   55篇
  1993年   54篇
  1992年   61篇
  1990年   49篇
  1989年   69篇
  1988年   45篇
  1987年   51篇
  1986年   55篇
  1985年   53篇
  1984年   55篇
  1983年   43篇
  1982年   30篇
  1981年   46篇
  1980年   26篇
  1979年   23篇
  1978年   22篇
  1977年   21篇
  1976年   31篇
  1975年   26篇
  1973年   16篇
  1970年   17篇
排序方式: 共有4445条查询结果,搜索用时 406 毫秒
21.
22.
The diffusion coefficient of the cationic dye Anilana Red BL in the anionically modified polyester fiber Dilana has been calculated regarding a general diffusion-immobilization model. In the model the mobile species are distinguished from the immobilized ones. In computations of Sand's equation and experimentally determined sorption isotherm of the dye in the fiber, the rate-of-dyeing curve and the concentration profiles of the dye in the same fiber were employed. The diffusion coefficient of the mobile species of Anilana Red BL in the fiber is two orders of magnitude higher than the average diffusion coefficient obtained from Hill's equation and the apparent diffusion coefficient calculated by the Boltzmann–Matano method.  相似文献   
23.
Testing the Ortega hypothesis: Facts and artifacts   总被引:2,自引:0,他引:2  
We examine the assumptions and data base used by researchers who have tested the Ortega hypothesis. We find that the assumptions are not supported by the data and that the data are faulty. We conclude that the results are artifactual. We recommend that any policy implemented on the basis of this research be suspended.  相似文献   
24.
Determining the status of privileged communications between psychologists and clients is a complex task. There is considerable variation across states with respect to the scope of psychologist–client privilege, and several sections of state codes directly and indirectly influence its status. An analysis of state laws related to privileged communication in the psychologist–client relationship is presented and prevalent legal exceptions and trends related to client privilege are discussed. Implications for practice to assist psychologists in balancing their ethical and legal obligations also are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
25.
Rates of poor psychological adjustment of children with sickle cell disease remained relatively constant over initial and follow-up assessment points. 50 children (aged 7–12 yrs) and their mothers completed the initial protocol. 30 children completed the follow-up plus 5 additional children and their mothers. These Ss were aged 7–24 yrs at follow-up. With initial levels of adjustment controlled, children's strategies for coping with pain accounted for a significant increment in child-reported symptoms and mother-reported internalizing behavior problems at follow-up beyond the contribution of illness and demographic parameters and follow-up interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
26.
In an effort to better understand the educational experiences and professional issues facing women in these fields, a survey of women alumnae was conducted. Respondents seemed fairly pleased with the education they received and were heavily influenced by personal aspects of the campus. Relationships with faculty members were described as their most beneficial and detrimental experiences. They particularly liked opportunities to apply their technical knowledge but did not believe there were enough opportunities for application. The need for more female role models and importance of involvement in student organizations were cited by many of the respondents. Self-confidence and good communication skills were rated as the most important qualities for professional success and advancement. Alumnae have pursued training experiences since graduation, but would like to see more opportunities to enhance communication and personal management skills and apply theoretical knowledge built into the undergraduate experience. The findings are discussed in relationship to previous research studies and recommendations are made to improve the technically oriented college environment.  相似文献   
27.
Political economists agree that a trade-off exists between equality and efficiency. Using a hypothetical society paradigm, the mean income (representing efficiency) and income variability (representing equality) of distributions of wealth and the correlation between wealth and effort within a society were manipulated. Ss made all pairwise comparisons of distributions within societies of differing meritocracy. A "maximin" principle best described trade-off resolution strategies when effort and outcome were weakly linked: People maximized the minimum standard of living within a society. A compromise principle best described preferences when income was tightly linked to effort: People rejected distributions in which some citizens fell below the "poverty line" but maximized efficiency above this constraint. Ideological polarization was pronounced under moderate meritocracy; here liberals could focus on the role of chance and conservatives on the role of effort and ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
28.
Innovation is often left to insight and serendipity. A lot of what researchers call innovation is actually a process by which one can make the individual consumer or practitioner more ‘creative’. Although it is important to work with the creative individual in hopes of coming up with the better ‘idea’ and new product/service opportunity, an equally valid albeit novel and counterintuitive approach systematizes creativity in a ‘research-driven machine’. This paper presents an approach to the systematization, based upon the point of view that creativity and innovation comprise the recombination of components into new blends. Given this point of view, to then spur innovation requires a systematic database that the user can access, with tools to help manipulate that database. The paper shows how such a database can be constructed and then used to create a novel product. The approach provides a general framework for the sensory professional to become more involved in the early stages of product development, where the focus is on the conceptual aspects of food features rather than on their physical manifestations in actual products.  相似文献   
29.
Observed visuographic and paranoid symptomatology in 26 dentists (mean age, 49.9 yrs) with elevated mercury levels. Neuropsychological functions were assessed with measures such as the Wechsler Adult Intelligence Scale (WAIS), the Bender-Gestalt Test, and the SCL-90 (Revised). Although the observed changes were mild, their presence suggests subtoxic hazards associated with dental practice and underscore a continual need for maintaining mercury hygiene. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
30.
We have designed a family of parallel data flow analysis algorithms for execution on distributed-memory MIMD machines, based on general-purpose, hybrid algorithms for data flow analysis [Marlowe and Ryder 1990]. We exploit a natural partitioning of the hybrid algorithms and explore a static mapping, dynamic scheduling strategy. Alternative mapping-scheduling choices and refinements of the flow graph condensation used are discussed. Our parallel hybrid algorithm family is illustrated on Reaching Definitions, although parallel algorithms also exist for many interprocedural (e.g., Aliasing) and intraprocedural (e.g., Available Expressions) problems [Marlowe 1989]. We have implemented the parallel hybrid algorithm for Reaching Definitions on an Intel iPSC/2. Our empirical results suggest the practicality of parallel hybrid algorithms.An earlier version of this paper was presented at Supercomputing '90.The research reported here was supported, in part, by the New Jersey Commission on Science and Technology and the CAIP Center's Industrial Members, by Siemens Research Corporation and by National Science Foundation grant CCR-8920078.  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