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   20226篇
  免费   2664篇
  国内免费   1613篇
电工技术   2525篇
技术理论   2篇
综合类   1978篇
化学工业   1151篇
金属工艺   329篇
机械仪表   1656篇
建筑科学   976篇
矿业工程   351篇
能源动力   409篇
轻工业   3125篇
水利工程   898篇
石油天然气   1152篇
武器工业   241篇
无线电   1826篇
一般工业技术   1650篇
冶金工业   440篇
原子能技术   139篇
自动化技术   5655篇
  2024年   147篇
  2023年   449篇
  2022年   895篇
  2021年   939篇
  2020年   932篇
  2019年   798篇
  2018年   741篇
  2017年   892篇
  2016年   889篇
  2015年   950篇
  2014年   1315篇
  2013年   1285篇
  2012年   1535篇
  2011年   1654篇
  2010年   1198篇
  2009年   1175篇
  2008年   1061篇
  2007年   1270篇
  2006年   1086篇
  2005年   859篇
  2004年   697篇
  2003年   605篇
  2002年   538篇
  2001年   383篇
  2000年   352篇
  1999年   273篇
  1998年   256篇
  1997年   232篇
  1996年   156篇
  1995年   155篇
  1994年   121篇
  1993年   99篇
  1992年   83篇
  1991年   71篇
  1990年   58篇
  1989年   54篇
  1988年   36篇
  1987年   28篇
  1986年   28篇
  1985年   15篇
  1984年   29篇
  1983年   14篇
  1982年   23篇
  1981年   22篇
  1980年   27篇
  1979年   14篇
  1978年   14篇
  1977年   8篇
  1961年   4篇
  1959年   8篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
11.
Reports an error in "Interactive use of lexical information in speech perception" by Cynthia M. Connine and Charles Clifton (Journal of Experimental Psychology: Human Perception and Performance, 1987[May], Vol 13[2], 291-299). In the aforementioned article, Figures 1 and 2 were inadvertently transposed. The figure on p. 294 is actually Figure 2, and the figure on p. 296 is actually Figure 1. The captions are correct as they stand. (The following abstract of the original article appeared in record 1987-23984-001.) Two experiments are reported that demonstrate contextual effects on identification of speech voicing continua. Experiment 1 demonstrated the infuence of lexical knowledge on identification of ambiguous tokens from word–nonword and nonword–word continua. Reaction times for word and nonword responses showed a word advantage only for ambiguous stimulus tokens (at the category boundary); no word advantage was found for clear stimuli (at the continua endpoints). Experiment 2 demonstrated an effect of a postperceptual variable, monetary payoff, on nonword–nonword continua. Identification responses were influenced by monetary payoff, but reaction times for bias-consistent and bias-inconsistent responses did not differ at the category boundary. An advantage for bias-consistent responses was evident at the continua endpoints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
12.
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   
13.
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   
14.
In this work, simple modifications on the cost index of particular local-model fuzzy clustering algorithms are proposed in order to improve the readability of the resulting models. The final goal is simultaneously providing local linear models (reasonably close to the plant’s Jacobian) and clustering in the input space so that desirable characteristics (regarding final model accuracy, and convexity and smoothness of the cluster membership functions) are improved with respect to other proposals in literature. Some examples illustrate the proposed approach.  相似文献   
15.
16.
Grey box identification refers to the practice of identifying dynamical systems in model structures exploiting partial prior information. This contribution reviews a method for stochastic grey box identification and surveys experiences and lessons of applying it to a number of industrial processes. Issues to be addressed include advantages and costs of introducing stochastics into the model, the question of what contribution must be expected from the model designer as opposed to what can be formalized in computer algorithms, and an outlook on future plans to resolve present shortcomings.  相似文献   
17.
本文利用选区电子衍射,并结合X射线衍射对六种不同成份的急冷合金及其退火后的相组成进行了鉴定,得到了它们的相组成。  相似文献   
18.
胡舟毅  袁道华  张严虎  何杰 《信息技术》2007,31(11):127-131
现在,养猪生产者滥用激素、微量元素和违禁药物饲养生猪,而消费者却无法识别这种猪肉,严重地威胁着消费者的食品卫生安全。为此,应用射频识别技术,采用综合软件管理,以一维条形码实行三网合一查验的方式来建立猪肉生产卫生安全跟踪系统,是保障消费者食品卫生安全的理想方法。  相似文献   
19.
20.
A method of approximate channel identification is proposed that is based on a simplification of the correlation estimator. Despite the numerical simplification (no multiplications or additions are required, only comparisons and an accumulator), the performance of the proposed estimator is not significantly worse than that of the standard correlation estimator. A free (user selectable) parameter moves ‘smoothly’ from a situation with small sum‐squared channel estimation error but hard‐to‐identify channel peaks, to one with a larger sum‐squared estimation error but easy‐to‐identify channel peaks. The proposed estimator is shown to be biased and its behaviour is analysed in a number of situations. Applications of the proposed estimator to sparsity detection, symbol timing recovery and to the initialization of blind equalizers are suggested. Copyright © 2002 John Wiley & Sons, Ltd.  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