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   10748篇
  免费   68篇
  国内免费   143篇
电工技术   212篇
综合类   9篇
化学工业   402篇
金属工艺   442篇
机械仪表   67篇
建筑科学   66篇
矿业工程   6篇
能源动力   63篇
轻工业   69篇
水利工程   20篇
石油天然气   28篇
武器工业   6篇
无线电   386篇
一般工业技术   223篇
冶金工业   75篇
原子能技术   112篇
自动化技术   8773篇
  2024年   5篇
  2023年   5篇
  2022年   16篇
  2021年   21篇
  2020年   9篇
  2019年   28篇
  2018年   20篇
  2017年   12篇
  2016年   18篇
  2015年   27篇
  2014年   238篇
  2013年   231篇
  2012年   793篇
  2011年   3106篇
  2010年   1170篇
  2009年   1042篇
  2008年   700篇
  2007年   593篇
  2006年   473篇
  2005年   578篇
  2004年   535篇
  2003年   596篇
  2002年   297篇
  2001年   16篇
  2000年   17篇
  1999年   27篇
  1998年   102篇
  1997年   32篇
  1996年   24篇
  1995年   7篇
  1994年   19篇
  1993年   11篇
  1992年   12篇
  1991年   9篇
  1990年   20篇
  1989年   8篇
  1988年   13篇
  1987年   10篇
  1986年   16篇
  1985年   11篇
  1984年   30篇
  1983年   19篇
  1982年   11篇
  1981年   10篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1977年   3篇
  1975年   2篇
  1969年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
We propose subspace distance measures to analyze the similarity between intrapersonal face subspaces, which characterize the variations between face images of the same individual. We call the conventional intrapersonal subspace average intrapersonal subspace (AIS) because the image differences often come from a large number of persons. An intrapersonal subspace is referred to as specific intrapersonal subspace (SIS) if the image differences are from just one person. We demonstrate that SIS varies significantly from person to person, and most SISs are not similar to AIS. Based on these observations, we introduce the maximum a posteriori (MAP) adaptation to the problem of SIS estimation, and apply it to the Bayesian face recognition algorithm. Experimental results show that the adaptive Bayesian algorithm outperforms the non-adaptive Bayesian algorithm as well as Eigenface and Fisherface methods if a small number of adaptation images are available.  相似文献   
82.
It was shown by Zames and Shneydor and later by Mossaheb that a high-frequency dither signal of a quite arbitrary shape can be used to narrow the effective nonlinear sector of Lipschitz continuous feedback systems. In this paper, it is shown that also discontinuous nonlinearities of feedback systems can be narrowed using dither, as long as the amplitude distribution function of the dither is absolutely continuous and has bounded derivative. The averaged system is proven to approximate the dithered system with an error of the order of dither period.  相似文献   
83.
84.
85.
In the last decade there was growing interest in strategic management literature about factors that influence a company's ability to use IT. There is general consensus that knowledge and competency are necessary in developing an IT capability, but there is very little understanding of what the necessary competencies are, and how they influence IS usage in different contexts. The small and medium-sized enterprise context is particularly interesting for two reasons: it constitutes a major part of the economy and it has been relatively unsuccessful in exploiting e-business.  相似文献   
86.
In this paper we consider the problem of constructing confidence regions for the parameters of nonlinear dynamical systems. The proposed method uses higher order statistics and extends the LSCR (leave-out sign-dominant correlation regions) algorithm for linear systems introduced in Campi and Weyer [2005, Guaranteed non-asymptotic confidence regions in system identification. Automatica 41(10), 1751-1764. Extended version available at 〈http://www.ing.unibs.it/∼campi〉]. The confidence regions contain the true parameter value with a guaranteed probability for any finite number of data points. Moreover, the confidence regions shrink around the true parameter value as the number of data points increases. The usefulness of the proposed approach is illustrated on some simple examples.  相似文献   
87.
The most efficient approach to a fair exchange is to use an off-line trusted third party (TTP for short) who gets involved only when a dispute between two parties occurs. However, exchanged secrets that are not protected properly may be exposed to the TTP when one of these two parties asks the TTP to mediate the dispute. The first work to protect exchanged secrets from TTP’s misuse was proposed by Franklin and Reiter in 1997. They provided an on-line semi-trusted third party instead of an off-line third party for a fair exchange. Their schemes forced the TTP to take part in the protocol for all the cases, and thus, deemed to be impractical.The present paper, introduces several models, including single and multiple TTPs, to focus the attention not only on security properties, but also on reliability functions. In the single TTP mode, our new scheme can protect the exchanged data through an efficient exchange protocol, whereas in the multiple TTP mode, we proposed an approach to balance the security level with the reliability of the system.  相似文献   
88.
Based on a polynomial operator approach, a new sparse controller structure is derived, which is actually an improved version of the recently proposed structure [Li, G. (2004). A polynomial-operator-based DFIIt structure for IIR filters. IEEE Transactions on Circuits and Systems II, 51, 147-151]. The performance of the proposed structure is analyzed by deriving the corresponding expression of roundoff noise gain and the problem of finding optimized sparse structures is solved efficiently with a genetic algorithm (GA). A numerical example is given, which shows that the newly developed structure can achieve much better performance than some well-known structures and particularly outperforms the traditional optimal fully parametrized realization greatly in terms of reducing roundoff noise and implementation complexity.  相似文献   
89.
This paper presents the physical design methodology of the VCI/SPIN wrappers. The challenge was the validation of the wrappers’ specification with Alliance CAD Tools.A wrapper is a standard gateway used by a subscriber to access an interconnect. Because there are as many wrappers as subscribers, it is relevant to have an estimation of the wrapper’s area, its frequency and then compare these results to the router’s.The interest to perform this study with academic tools is to show that commercial tools are not the unique way for experimentations.  相似文献   
90.
This paper presents a robust rule-based approach for the splitting of binary clumps that are formed by objects of diverse shapes and sizes. First, the deepest boundary pixels, i.e., the concavity pixels in a clump, are detected using a fast and accurate scheme. Next, concavity-based rules are applied to generate the candidate split lines that join pairs of concavity pixels. A figure of merit is used to determine the best split line from the set of candidate lines. Experimental results show that the proposed approach is robust and accurate.  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