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   9964篇
  免费   69篇
  国内免费   4篇
电工技术   141篇
化学工业   446篇
金属工艺   288篇
机械仪表   77篇
建筑科学   69篇
能源动力   48篇
轻工业   214篇
水利工程   13篇
石油天然气   5篇
无线电   331篇
一般工业技术   213篇
冶金工业   160篇
原子能技术   87篇
自动化技术   7945篇
  2024年   5篇
  2023年   9篇
  2022年   44篇
  2021年   56篇
  2020年   34篇
  2019年   36篇
  2018年   39篇
  2017年   40篇
  2016年   42篇
  2015年   23篇
  2014年   242篇
  2013年   224篇
  2012年   820篇
  2011年   2324篇
  2010年   1150篇
  2009年   994篇
  2008年   705篇
  2007年   612篇
  2006年   476篇
  2005年   591篇
  2004年   534篇
  2003年   586篇
  2002年   279篇
  2001年   11篇
  2000年   12篇
  1999年   9篇
  1998年   37篇
  1997年   18篇
  1996年   14篇
  1995年   10篇
  1994年   7篇
  1993年   7篇
  1992年   5篇
  1991年   2篇
  1990年   5篇
  1989年   2篇
  1988年   5篇
  1987年   3篇
  1986年   2篇
  1985年   3篇
  1983年   2篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1976年   4篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
The patterning of contact holes by selecting out-of-focus image plane (defocus) using attenuated phase shift masks (APSM) has been studied. Defocus is found to enhance the image modulation at low partial coherence for contact holes with negative local average of mask function. Semi-dense holes up to 130 nm in 8% APSM have been printed by 0.5 μm defocus at a partial coherence of 0.31 using KrF scanner with highest numerical aperture of 0.68. However, these holes were closed with in-focus imaging. Defocus is also found to be beneficial for patterning the pitches that have extensive side lobes with in-focus imaging.  相似文献   
3.
4.
In this article 1 describe efforts to build a genetically informative, population-based sample of black twins to study physical frailty and aging in the United States. This project involves the use of governmental registries combined with sampling techniques developed to overcome limitations in the registry data. Two analytical approaches to measures of disability are included to illustrate the types of questions that can be addressed with this sample. These results suggest that physical disability in late life has both genetic and environmental determinants. Only with a genetically informative sample can evidence be collected indicating that frailty may be driven by fixed processes (i.e., disability resulting from activation of senescence genes), fluid processes (i.e., disability resulting from changes in the features of the environment), or a combination of both.  相似文献   
5.
A stochastic realization problem of a stationary stochastic process is re-visited, and a new stochastically balanced realization algorithm is derived in a Hilbert space generated by second-order stationary processes. The present algorithm computes a stochastically balanced realization by means of the singular value decomposition of a weighted block Hankel matrix derived by a “block LQ decomposition”. Extension to a stochastic subspace identification method explains how the proposed abstract algorithm is implemented in system identification.  相似文献   
6.
7.
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   
8.
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   
9.
10.
This paper proposes a frequency domain algorithm for Wiener model identifications based on exploring the fundamental frequency and harmonics generated by the unknown nonlinearity. The convergence of the algorithm is established in the presence of white noise. No a priori knowledge of the structure of the nonlinearity is required and the linear part can be nonparametric.  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