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   58390篇
  免费   5511篇
  国内免费   3153篇
电工技术   3264篇
技术理论   1篇
综合类   3928篇
化学工业   8007篇
金属工艺   3108篇
机械仪表   3232篇
建筑科学   3496篇
矿业工程   1312篇
能源动力   1187篇
轻工业   5517篇
水利工程   1129篇
石油天然气   2010篇
武器工业   464篇
无线电   6092篇
一般工业技术   5732篇
冶金工业   2004篇
原子能技术   663篇
自动化技术   15908篇
  2024年   276篇
  2023年   816篇
  2022年   1587篇
  2021年   2047篇
  2020年   1569篇
  2019年   1362篇
  2018年   1551篇
  2017年   1675篇
  2016年   1603篇
  2015年   2179篇
  2014年   2934篇
  2013年   3478篇
  2012年   4542篇
  2011年   6459篇
  2010年   4912篇
  2009年   4680篇
  2008年   4253篇
  2007年   3935篇
  2006年   3518篇
  2005年   3111篇
  2004年   2336篇
  2003年   1975篇
  2002年   1595篇
  2001年   1113篇
  2000年   843篇
  1999年   642篇
  1998年   389篇
  1997年   322篇
  1996年   270篇
  1995年   208篇
  1994年   176篇
  1993年   151篇
  1992年   109篇
  1991年   94篇
  1990年   62篇
  1989年   53篇
  1988年   39篇
  1987年   35篇
  1986年   26篇
  1985年   13篇
  1984年   11篇
  1983年   11篇
  1982年   17篇
  1980年   7篇
  1979年   11篇
  1978年   9篇
  1977年   10篇
  1976年   13篇
  1975年   9篇
  1970年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
This paper presents a system that can perform pedestrian detection and tracking using vision-based techniques. A very important issue in the field of intelligent transportation system is to prevent pedestrians from being hit by vehicles. Recently, a great number of vision-based techniques have been proposed for this purpose. In this paper, we propose a vision-based method, which combines the use of a pedestrian model as well as the walking rhythm of pedestrians to detect and track walking pedestrians. Through integrating some spatial and temporal information grabbed by a vision system, we are able to develop a reliable system that can be used to prevent traffic accidents happened at crossroads. In addition, the proposed system can deal with the occlusion problem. Experimental results obtained by executing some real world cases have demonstrated that the proposed system is indeed superb.  相似文献   
93.
In this article, we present a parallel image processing system based on the concept of reactive agents. Our system lies in the oRis language, which allows to describe finely and simply the agents’ behaviors to detect image features. We also present a method of segmentation using a multi-agent system, and two biological applications made with oRis. The stopping of this multi-agent system is implemented through a technique issued from immunology: the apoptosis.  相似文献   
94.
Automated currency validation requires a decision to be made regarding the authenticity of a banknote presented to the validation system. This decision often has to be made with little or no information regarding the characteristics of possible counterfeits as is the case for issues of new currency. A method for automated currency validation is presented which segments the whole banknote into different regions, builds individual classifiers on each region and then combines a small subset of the region specific classifiers to provide an overall decision. The segmentation and combination of region specific classifiers to provide optimized false positive and false negative rates is achieved by employing a genetic algorithm. Experiments based on high value notes of Sterling currency were carried out to assess the effectiveness of the proposed solution.  相似文献   
95.
Many computer vision problems can be formulated as optimization problems. Presented in this paper is a new framework based on the quadtree-based genetic algorithm that can be applied to solve many of these problems. The proposed algorithm incorporates the quadtree structure into the conventional genetic algorithm. The solutions of image-related problems are encoded through encoding the corresponding quadtrees, and therefore, the 2D locality within a solution can be preserved. Examples addressed using the proposed framework include image segmentation, stereo vision, and motion estimation. In all cases, encouraging results are obtained.  相似文献   
96.
This paper presents a method to design an output-feedback controller that simultaneously solves global asymptotic stabilization and tracking of an underactuated omni-directional intelligent navigator—a spherical underwater vehicle moving in a horizontal plane (i.e. at a constant depth). The vehicle does not have a sway actuator and has only position and orientation measurements available. The control development is based on Lyapunov's direct method, backstepping technique and use of interconnected structure of the vehicle dynamics. Numerical simulations demonstrate the results.  相似文献   
97.
98.
The problem of controlling nonlinear noisy systems affected by parametric uncertainties is approached via the introduction of a supervisor which, whenever needed, switches on, in feedback to the plant, a controller selected from a finite set of predesigned controllers. A Lyapunov-based falsification criterion allows one to ensure robust stability in the presence of uncertain constant parameters and exogenous bounded disturbances. Simulations are discussed in order to illustrate the merits of the proposed algorithms.  相似文献   
99.
100.
赵婧华  卢敏 《电子工程师》2004,30(11):37-39
空时分集技术的最大优点在于在不增加带宽的情况下可以提高系统的可靠性,是目前移动通信的研究热点.常模算法是一种性能优良的码分多址(CDMA)盲多用户检测技术,能确保判决信号与实际传送信号之间的差错较小,误码率性能良好.文中提出将标准线性受限常模算法(LCCMA)与空时分组码(STBC)相结合,设计出一种收敛快、能够改善系统性能的基于2-空时分组码的多用户接收机.  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