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   197415篇
  免费   3164篇
  国内免费   842篇
电工技术   3720篇
综合类   822篇
化学工业   29342篇
金属工艺   6440篇
机械仪表   5886篇
建筑科学   5483篇
矿业工程   777篇
能源动力   4449篇
轻工业   19740篇
水利工程   1779篇
石油天然气   671篇
武器工业   9篇
无线电   22800篇
一般工业技术   32881篇
冶金工业   44766篇
原子能技术   2569篇
自动化技术   19287篇
  2021年   965篇
  2018年   1619篇
  2017年   1879篇
  2016年   2412篇
  2015年   1903篇
  2014年   2349篇
  2013年   7204篇
  2012年   5461篇
  2011年   7251篇
  2010年   4431篇
  2009年   5078篇
  2008年   5419篇
  2007年   5731篇
  2006年   5034篇
  2005年   7509篇
  2004年   6634篇
  2003年   6040篇
  2002年   4876篇
  2001年   4791篇
  2000年   4102篇
  1999年   4390篇
  1998年   12783篇
  1997年   9012篇
  1996年   6948篇
  1995年   5152篇
  1994年   4463篇
  1993年   4349篇
  1992年   3056篇
  1991年   3008篇
  1990年   2945篇
  1989年   2899篇
  1988年   2770篇
  1987年   2399篇
  1986年   2330篇
  1985年   2756篇
  1984年   2421篇
  1983年   2299篇
  1982年   2226篇
  1981年   2191篇
  1980年   2065篇
  1979年   1969篇
  1978年   1894篇
  1977年   2683篇
  1976年   3810篇
  1975年   1702篇
  1974年   1486篇
  1973年   1515篇
  1972年   1243篇
  1971年   1170篇
  1970年   993篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
The Tera-op reliable intelligently adaptive processing system (TRIPS) architecture seeks to deliver system-level configurability to applications and runtime systems. It does so by employing the concept of polymorphism, which permits the runtime system to configure the hardware execution resources to match the mode of execution and demands of the compiler and application.  相似文献   
922.
Two experiments involving 99 undergraduate participants sought to examine the influence of mood states on encoding speed within lexical decision and pronunciation tasks. Mood states were measured naturalistically in Experiment 1 and manipulated in Experiment 2. Stimuli consisted of nouns representing useful (e.g., food) and nonuseful (e.g., lint) objects. Mood states had no implications for initial encoding speed. However, when the same words were presented a 2nd time (i.e., repeated), happy individuals displayed a tendency to encode useful words faster than nonuseful ones. Thus, mood states influenced repetition priming on the basis of stimulus valence. The authors propose that happiness sensitizes individuals to useful or rewarding objects, which in turn creates a stronger memory trace for such stimuli in the future. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
923.
924.
925.
This study provides a meta-analysis of research on the associations between relationship conflict, task conflict, team performance, and team member satisfaction. Consistent with past theorizing, results revealed strong and negative correlations between relationship conflict, team performance, and team member satisfaction. In contrast to what has been suggested in both academic research and introductory textbooks, however, results also revealed strong and negative (instead of the predicted positive) correlations between task conflict, team performance, and team member satisfaction. As predicted, conflict had stronger negative relations with team performance in highly complex (decision making, project, mixed) than in less complex (production) tasks. Finally, task conflict was less negatively related to team performance when task conflict and relationship conflict were weakly, rather than strongly, correlated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
926.
Hybrid Approach for Addressing Uncertainty in Risk Assessments   总被引:3,自引:0,他引:3  
Parameter uncertainty is a major aspect of the model-based estimation of the risk of human exposure to pollutants. The Monte Carlo method, which applies probability theory to address model parameter uncertainty, relies on a statistical representation of available information. In recent years, other uncertainty theories have been proposed as alternative approaches to address model parameter uncertainty in situations where available information is insufficient to identify statistically representative probability distributions, due in particular to data scarcity. The simplest such theory is possibility theory, which uses so-called fuzzy numbers to represent model parameter uncertainty. In practice, it may occur that certain model parameters can be reasonably represented by probability distributions, because there are sufficient data available to substantiate such distributions by statistical analysis, while others are better represented by fuzzy numbers (due to data scarcity). The question then arises as to how these two modes of representation of model parameter uncertainty can be combined for the purpose of estimating the risk of exposure. This paper proposes an approach (termed a hybrid approach) which combines Monte Carlo random sampling of probability distribution functions with fuzzy calculus. The approach is applied to a real case of estimation of human exposure, via vegetable consumption, to cadmium present in the surficial soils of an industrial site located in the north of France. The application illustrates the potential of the proposed approach, which allows the uncertainty affecting model parameters to be represented in a way that is consistent with the information at hand. Also, because the hybrid approach takes advantage of the “rich” information provided by probability distributions, while retaining the conservative character of fuzzy calculus, it is believed to hold value in terms of a “reasonable” application of the precautionary principle.  相似文献   
927.
928.
929.
930.
R.A. McMahon  M.P. Smith  K.A. Seffen  W. Anwand 《Vacuum》2007,81(10):1301-1305
Flash-lamp annealing (FLA) on a millisecond time scale has been shown to be a promising tool in the preparation of high-quality semiconducting materials. The process imposes time varying through-thickness temperature profiles on the substrates being processed, and consequently thermal stresses. A combined thermal and optical model has been developed to predict the substrate temperature distribution and this model has been linked to a structural model to compute stresses and deflections. The paper shows how these models can be used to explore process conditions in flash lamp annealing, with particular regard to the annealing of ion implants in silicon and the crystallization of amorphous silicon layers on glass substrates.  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