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   13854篇
  免费   949篇
  国内免费   110篇
电工技术   209篇
综合类   61篇
化学工业   3599篇
金属工艺   353篇
机械仪表   501篇
建筑科学   518篇
矿业工程   22篇
能源动力   964篇
轻工业   1294篇
水利工程   189篇
石油天然气   224篇
武器工业   4篇
无线电   1421篇
一般工业技术   2603篇
冶金工业   495篇
原子能技术   97篇
自动化技术   2359篇
  2024年   70篇
  2023年   273篇
  2022年   593篇
  2021年   904篇
  2020年   762篇
  2019年   825篇
  2018年   927篇
  2017年   838篇
  2016年   822篇
  2015年   487篇
  2014年   763篇
  2013年   1386篇
  2012年   920篇
  2011年   982篇
  2010年   675篇
  2009年   619篇
  2008年   447篇
  2007年   368篇
  2006年   308篇
  2005年   199篇
  2004年   176篇
  2003年   154篇
  2002年   124篇
  2001年   91篇
  2000年   92篇
  1999年   82篇
  1998年   139篇
  1997年   114篇
  1996年   97篇
  1995年   68篇
  1994年   51篇
  1993年   59篇
  1992年   46篇
  1991年   38篇
  1990年   40篇
  1989年   32篇
  1988年   25篇
  1987年   24篇
  1986年   34篇
  1985年   27篇
  1984年   27篇
  1983年   25篇
  1982年   21篇
  1981年   19篇
  1980年   19篇
  1979年   16篇
  1978年   18篇
  1977年   18篇
  1976年   25篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Mahdavi  Ali 《Water Resources Management》2019,33(10):3615-3631
Water Resources Management - This work presents an analytical solution for the linearized Boussinesq equation describing the nature of well hydraulics in equilateral triangular-shaped unconfined...  相似文献   
3.
This paper deals with the problem of designing a robust static output feedback controller for polytopic systems. The current research that tackled this problem is mainly based on LMI method, which is conservative by nature. In this paper, a novel approach is proposed, which considers the design space of the controller parameters and iteratively partitions the space to small simplexes. Then, by assessing the stability in each simplex, the solution space for design parameters is directly determined. It has been theoretically proved that, if there exists a feasible solution in the design space, the algorithm can find it. To validate the result of the proposed approach, comparative simulation examples are given to illustrate the performance of the design methodology as compared to those of previous approaches.  相似文献   
4.
5.
6.
7.
Wireless Networks - The original version of this article unfortunately contained a mistake in the title. The correct title has been published with this erratum.  相似文献   
8.
Multimedia Tools and Applications - The world is facing many problems including that of traffic congestion. To highlight the issue of traffic congestion worldwide specially in urban areas and to...  相似文献   
9.
Thermal bending analysis of doubly curved laminated shell panels with general boundary conditions and laminations is presented. The equations of equilibrium are derived in the form of two coupled sets of ordinary differential equations based on a general shell theory and solved through the state-space approach in a repeated manner. It is depicted that the results of the present method are in great agreement with analytical solutions. Cylindrical shell panels with general boundary conditions and laminations, where no analytical solution is available, are solved. It is found that the present method exhibits a high convergence rate as well as presenting accurate results in all cases.  相似文献   
10.
Anisoplanatic electromagnetic (EM) propagation across a turbulent atmosphere has been recently examined for an unmodulated carrier propagating over an image-bearing transparency through optical lensing, and for the embedded information inside a carrier recovered using heterodyning and digital demodulation. Carrier modulation yielded better recovery than simple lens-based imaging. A possible mitigation strategy is proposed whereby the image information is encrypted on an RF chaotic carrier, thereafter secondarily embedded onto an optical carrier. Results based on the modified von Karman (MVKS) and the Hufnagel-Valley (H-V) models showed that the signal/image recovery under turbulence is improved compared with non-chaotic propagation. The case of time-varying/dynamic images is also taken up; it is demonstrated via cross-correlation products that turbulence is mitigated by the use of chaotic carrier encryption. Overall, transmission via chaos offers mitigation against distortions due to turbulence along with the security feature inherent via the chaos keys which prevent signal recovery without key-matching.  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