首页 | 官方网站   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   1822篇
  免费   35篇
工业技术   1857篇
  2019年   11篇
  2018年   19篇
  2017年   15篇
  2016年   19篇
  2015年   27篇
  2014年   31篇
  2013年   100篇
  2012年   50篇
  2011年   81篇
  2010年   57篇
  2009年   76篇
  2008年   66篇
  2007年   73篇
  2006年   79篇
  2005年   76篇
  2004年   72篇
  2003年   48篇
  2002年   63篇
  2001年   57篇
  2000年   38篇
  1999年   40篇
  1998年   62篇
  1997年   56篇
  1996年   45篇
  1995年   35篇
  1994年   38篇
  1993年   36篇
  1992年   37篇
  1991年   13篇
  1990年   30篇
  1989年   20篇
  1988年   16篇
  1987年   18篇
  1986年   20篇
  1985年   30篇
  1984年   31篇
  1983年   25篇
  1982年   17篇
  1981年   17篇
  1980年   18篇
  1979年   14篇
  1978年   14篇
  1977年   19篇
  1976年   26篇
  1975年   10篇
  1974年   14篇
  1973年   14篇
  1972年   11篇
  1971年   10篇
  1970年   9篇
排序方式: 共有1857条查询结果,搜索用时 234 毫秒
1.
2.
Terry.lee 《程序员》2004,(4):21-22
本部分将讲述PortletConfig对象及其PortletContext对象的概念及应用。  相似文献   
3.
Several N-(phosphonomethyl) amides have previously been reported to act as particularly effective flame retardants for cellulose. It has also been demonstrated previously that the efficiency of a flame retardant on cellulose frequently parallels its ability to phosphorylate cellulosic hydroxyls at elevated temperatures. This study of the hydrolysis and alcoholysis reactions of N-(phosphonomethyl) amides establishes their unique reactivity. An explanation for this high reactivity is proposed on the basis of intramolecular assistance of the attack of water or alcohols at phosphorus by the carbonyl oxygen of the amide moiety.  相似文献   
4.
The impact of fouling on the operation of submerged membrane bioreactors (MBRs) is discussed. The discussion proceeds through a review of the impacts of fouling and fouling speciation, with correlations of filterability against candidate foulants being provided. There follows a brief comparison of hydraulic performance of the submerged and sidestream configurations: data is presented to demonstrate the efficacy of coarse bubble aeration in the submerged MBR. The critical flux concept is then discussed and its applicability to MBRs deliberated in view of recent publications demonstrating fouling under sub-critical flux conditions. Finally, the two most commercially important MBR products are briefly reviewed with specific reference to design and operation for fouling amelioration.  相似文献   
5.
6.
We have devised a new scheme for coding designers' cognitive actions from video/audio design protocols. Designers' actions are coded into four cognitive levels; physical, perceptual, functional and conceptual. Relations between actions belonging to different levels, such as dependencies and triggering relations, are also coded. The present scheme has two benefits. First, we found that design actions are definable in a systematic way using the vocabulary of the scheme, and thus a designer's cognitive behaviours in each of local design stages is represented as a structure composed of defined primitive actions. This is expected to lay the foundation for microscopic analyses of how particular types of actions contribute to the formation of key design ideas. Second, this scheme is suitable for macroscopic analyses of how designers cognitively interact with their own sketches. We examined, for a practising architect, the ways in which drawing, inspection of drawings, perception, and functional thoughts correlated with one another in his design process. The findings suggest that design sketches serve not only as external memory or as a provider of visual cues for association of non-visual information, but also as a physical setting in which design thoughts are constructed on the fly.  相似文献   
7.
8.
9.
Various measures, such as Margin and Bias/Variance, have been proposed with the aim of gaining a better understanding of why Multiple Classifier Systems (MCS) perform as well as they do. While these measures provide different perspectives for MCS analysis, it is not clear how to use them for MCS design. In this paper a different measure based on a spectral representation is proposed for two-class problems. It incorporates terms representing positive and negative correlation of pairs of training patterns with respect to class labels. Experiments employing MLP base classifiers, in which parameters are fixed but systematically varied, demonstrate the sensitivity of the proposed measure to base classifier complexity.  相似文献   
10.
Models and methods are presented for determining practical limits of the packing density of TRISO particles in fuel pebbles for a pebble-bed reactor (PBR). These models are devised for designing and interpreting fuel testing experiments. Two processes for particle failure are accounted for: failure of touching particles at the pressing stage in the pebble manufacturing process and failure due to inner pressure buildup during irradiation. The second process gains importance with increasing fuel temperature, which limits the particle packing density and the corresponding fuel enrichment. Suggestions for improvements to the models are presented.  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-23

京公网安备 11010802026262号