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   5368篇
  免费   125篇
  国内免费   10篇
电工技术   74篇
综合类   4篇
化学工业   824篇
金属工艺   109篇
机械仪表   75篇
建筑科学   235篇
矿业工程   16篇
能源动力   171篇
轻工业   437篇
水利工程   32篇
石油天然气   13篇
无线电   463篇
一般工业技术   700篇
冶金工业   1710篇
原子能技术   58篇
自动化技术   582篇
  2021年   35篇
  2019年   58篇
  2018年   48篇
  2017年   57篇
  2016年   70篇
  2015年   59篇
  2014年   68篇
  2013年   229篇
  2012年   121篇
  2011年   173篇
  2010年   143篇
  2009年   147篇
  2008年   171篇
  2007年   154篇
  2006年   146篇
  2005年   148篇
  2004年   128篇
  2003年   121篇
  2002年   146篇
  2001年   96篇
  2000年   89篇
  1999年   110篇
  1998年   351篇
  1997年   257篇
  1996年   153篇
  1995年   135篇
  1994年   145篇
  1993年   129篇
  1992年   84篇
  1991年   71篇
  1990年   77篇
  1989年   68篇
  1988年   78篇
  1987年   55篇
  1986年   70篇
  1985年   89篇
  1984年   89篇
  1983年   71篇
  1982年   67篇
  1981年   74篇
  1980年   59篇
  1979年   48篇
  1978年   41篇
  1977年   84篇
  1976年   121篇
  1975年   69篇
  1974年   51篇
  1973年   60篇
  1972年   51篇
  1970年   38篇
排序方式: 共有5503条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
This study addressed two main questions: (a) Are adolescent sons and daughters exposed to sensitive maternal disclosures after divorce with similar frequency and in similar detail? and (b) Does gender act as a moderator in the association between maternal disclosures and adolescent adjustment difficulties? Forced-choice and open-ended data were collected from 194 adolescents within 2 years after their parents' divorce. Quantitative analyses revealed that although the majority of adolescents experience some level of maternal disclosure, neither frequency nor detail of maternal disclosure differed as a function of adolescent gender. Frequent and detailed maternal disclosures were associated with adolescent adjustment difficulties, primarily psychological distress. Gender did not moderate that significant association. Qualitative analysis shed light on the link between maternal disclosures and adolescent distress, suggested the importance of how disclosures are made, and revealed several gender differences in reactions to maternal disclosures. Implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Removal of gold from basic solutions containing [Au(CN)2]? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry  相似文献   
6.
A semiconductor laser rate equation theory is presented that describes sideband injection locking under both weak optical injection and current modulation. By simultaneous optical injection and current modulation, control of both the phase and the frequency of a semiconductor laser is demonstrated. The phase-locked semiconductor laser operates at a different frequency to the optical injection source, with a frequency-difference given by the current modulation frequency. This method can be used to produce broadband sources, such as those producing ultrashort pulses and those required for coherent control, or to create high-frequency electronic oscillator sources with phase control by interference beating  相似文献   
7.
Research was undertaken to understand how to provide the most appropriate support for novice designers in engineering design. However, how designers apply their experience and knowledge is not understood and further research in this area is required. This paper describes an observational study to understand how novice and experienced designers approach design tasks. Electronic Publication  相似文献   
8.
A new multi-spectral laser radar (ladar) system based on the time-correlated single photon counting, time-of-flight technique has been designed to detect and characterise distributed targets at ranges of several kilometres. The system uses six separated laser channels in the visible and near infrared part of the electromagnetic spectrum. The authors present a method to detect the numbers, positions, heights and shape parameters of returns from this system, used for range profiling and target classification. The algorithm has two principal stages: non-parametric bump hunting based on an analysis of the smoothed derivatives of the photon count histogram in scale space, and maximum likelihood estimation using Poisson statistics. The approach is demonstrated on simulated and real data from a multi-spectral ladar system, showing that the return parameters can be estimated to a high degree of accuracy.  相似文献   
9.
The pipelined architecture and parallel organization of the AT&T Pixel Machine image computer are described and demonstrated with applications for the visualization of multidimensional fractals, particularly linear fractals and quaternion/ stacked Julia sets. Techniques for pushing the Pixel Machine to its peak abilities are described and apply to more recent parallel image computers as well.  相似文献   
10.
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