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   7312篇
  免费   456篇
  国内免费   42篇
工业技术   7810篇
  2023年   97篇
  2022年   224篇
  2021年   300篇
  2020年   226篇
  2019年   295篇
  2018年   409篇
  2017年   309篇
  2016年   336篇
  2015年   256篇
  2014年   337篇
  2013年   657篇
  2012年   366篇
  2011年   462篇
  2010年   369篇
  2009年   342篇
  2008年   296篇
  2007年   222篇
  2006年   246篇
  2005年   151篇
  2004年   155篇
  2003年   176篇
  2002年   127篇
  2001年   106篇
  2000年   119篇
  1999年   96篇
  1998年   130篇
  1997年   75篇
  1996年   72篇
  1995年   61篇
  1994年   54篇
  1993年   48篇
  1992年   40篇
  1991年   42篇
  1990年   30篇
  1989年   32篇
  1988年   39篇
  1987年   57篇
  1986年   34篇
  1985年   41篇
  1984年   36篇
  1983年   37篇
  1982年   24篇
  1981年   24篇
  1980年   28篇
  1979年   24篇
  1978年   28篇
  1977年   27篇
  1976年   36篇
  1975年   25篇
  1973年   19篇
排序方式: 共有7810条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Using Java-based tools in multimedia collaborative environments accessed over the Internet can increase an application's client base. Most operating systems support Java, and its "compile once-run everywhere" architecture is easy to maintain and update. The Java-based tools presented here let users share Internet resources, including resources originally designed for single use.  相似文献   
7.
We have developed a narrow-band controller in the MHz range, based on a field-programmable gate array. It is used to control the probe beam intensity in frequency-modulated spectroscopy experiments with an acoustooptic modulator. The residual amplitude modulation at the modulation frequency (2.5 MHz) is reduced by 50 dB. The first-harmonic detection of the signals is operated in saturation spectroscopy of I/sub 2/ at 514.5 nm and 501.7 nm. A reduction of the background noise and a large increase in the signal-to-noise ratio are obtained.  相似文献   
8.
9.
In the present work, the distribution of the random toughness characteristics (i.e. critical energy release rate, G1c) has been evaluated on the basis of experimental observations. Fracture test results from three groups of geometrically similar concrete specimens of size (width×total depth×thickness), 420×420×50–1680×1680×200 mm3, made with different maximum aggregate size of 9.5, 19, 38, and 76 mm were analyzed using a recently proposed distribution of extremes. In applications of probability, it is important to use an appropriate distribution type and adequate techniques for estimating the parameters of distribution. In this study, a new type distribution of minima is employed for probability computations. It was noticed that the entropy of distribution increases with the crack length, i.e. the uncertainty of toughness, G1c, value increases with crack length. A non-linear reduction of the maximum allowable splitting force with the defect size, a, was noticed. For large specimens, the maximum allowable splitting load is more sensitive to the required reliability level than that for small specimens. Reliability increases with aggregate size when all other conditions were constant.  相似文献   
10.
Conducted a study of client expectations of psychological services in Yucatán, Mexico, under the sponsorship of a grant from the Organization of American States. The Expectations about Counseling–Brief form (EAC-B) questionnaire was translated and administered to 488 subjects across age, sex, and experience with psychological services. Subsequent analyses supported the reliability and robustness of the Spanish EAC-B, with factor structure similar to the EAC-B in English. Some relation was found among age, sex, prior counseling experience, and expectations about counseling. Implications of these data for future research and comparison with U.S. subjects are discussed. (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-23

京公网安备 11010802026262号