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   5542篇
  免费   198篇
  国内免费   272篇
电工技术   59篇
综合类   230篇
化学工业   71篇
金属工艺   90篇
机械仪表   429篇
建筑科学   195篇
矿业工程   52篇
能源动力   40篇
轻工业   37篇
水利工程   15篇
石油天然气   47篇
武器工业   21篇
无线电   293篇
一般工业技术   217篇
冶金工业   36篇
原子能技术   9篇
自动化技术   4171篇
  2024年   14篇
  2023年   90篇
  2022年   138篇
  2021年   168篇
  2020年   94篇
  2019年   71篇
  2018年   83篇
  2017年   91篇
  2016年   129篇
  2015年   149篇
  2014年   286篇
  2013年   262篇
  2012年   240篇
  2011年   365篇
  2010年   237篇
  2009年   307篇
  2008年   350篇
  2007年   338篇
  2006年   374篇
  2005年   265篇
  2004年   273篇
  2003年   261篇
  2002年   252篇
  2001年   177篇
  2000年   154篇
  1999年   183篇
  1998年   108篇
  1997年   91篇
  1996年   70篇
  1995年   67篇
  1994年   62篇
  1993年   60篇
  1992年   44篇
  1991年   27篇
  1990年   25篇
  1989年   19篇
  1988年   13篇
  1987年   12篇
  1986年   3篇
  1985年   15篇
  1984年   6篇
  1983年   6篇
  1982年   5篇
  1981年   6篇
  1980年   3篇
  1979年   5篇
  1978年   5篇
  1976年   3篇
  1974年   2篇
  1956年   1篇
排序方式: 共有6012条查询结果,搜索用时 395 毫秒
11.
Many problems consist in splitting a set of objects into different groups so that each group verifies some properties. In practice, a partitioning is often encoded by an array mapping each object to its group numbering. In fact, the group number of an object does not really matter, and one can simply rename each group to obtain a new encoding. That is what we call the symmetry of the search space in a partitioning problem. This property may be prejudicial for optimization methods such as evolutionary algorithms (EA) which require some diversity during the search.  相似文献   
12.
Nowadays any Knowledge Based System (KBS) realization needs of intercommunication among distributed components and to use non-connected and distributed data sources, which poses several challenges to the classical Artificial Intelligence field of KBS.

The multiagent paradigm and the use of ontologies are considered to be suitable tools to face the problems of designing and developing today KBS. On the other hand, using such networked KBS through handheld devices makes more efficient exploitation and interaction with the system.

This paper presents an open and flexible architecture for a distributed KBS and an application of it to construct a system for Psychological Disorders consulting, the so called PDA2 (Psychological Disorder Assistant through PDA). We analyze the main features of the architecture as well as the agent tools we may use to construct it. Additionally, we present a support ontology for Psychological Disorders.  相似文献   

13.
14.
15.
We present a linear time approximation algorithm with a performance ratio of 1/2 for finding a maximum weight matching in an arbitrary graph. Such a result is already known and is due to Preis [STACS'99, Lecture Notes in Comput. Sci., Vol. 1563, 1999, pp. 259-269]. Our algorithm uses a new approach which is much simpler than the one given by Preis and needs no amortized analysis for its running time.  相似文献   
16.
17.
The authors performed a meta-analysis based on 169 conditions, gathered from 80 laboratory studies, to estimate the validity of the Guilty Knowledge Test (GKT) with the electrodermal measure. The over-all average effect size was 1.55, but there were considerable variations among studies. In particular, mock-crime studies produced the highest average effect size (2.09). Three additional moderators, were identified: Motivational instructions, deceptive ("no") verbal responses, and the use of at least 5 questions were associated with enhanced validity. Finally, a set of 10 studies that best approximated applications of the GKT under optimal conditions produced an average effect size of 3.12. The authors discuss factors that might limit the generalizability of these results and recommend further research of the GKT in realistic setups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
18.
This paper demonstrates how the problem of tracking targets, which appear as either straight or curved lines in two-dimensional display images (or data images) can be formulated in terms of a directed weighted graph model and how dynamic programming techniques can be efficiently applied to reach an optimal or sub-optimal solution. In general, track detection algorithms providing optimal solutions have good detective ability, but most of them suffer from the inability to detect discontinuous lines or to resolve efficiently pairs of crossing lines. A sub-optimal solution is provided that efficiently overcomes these weaknesses. We focus on modeling the track detection problem in terms of a graph, formulating fast sequential/parallel sub-optimal track detection algorithms and testing them on simulated data in order to show their detective ability. Moreover, we specify the conditions under which sub-optimal algorithms can perform at least as well as their corresponding optimal algorithms. This is significant for the track detection problem where fast, accurate and real-time detection is considered a necessity.  相似文献   
19.
MKR──一种有效的增量式概念获取系统   总被引:1,自引:0,他引:1       下载免费PDF全文
阮俊杰 《软件学报》1994,5(4):28-34
本文对示例式学习的ID5R算法进行了深入的研究并作了进一步的改进,提高了其计算效率.并提出一种适合于增量式学习的抗干扰机制,拓广了算法的适用范围.  相似文献   
20.
知识驱动的UG中的产品开发   总被引:2,自引:0,他引:2  
重点论述了UG中的KBE即KF模块的知识驱动产品开发设计过程及其关键技术,介绍了知识驱动自动化过程,实例剖析了UG中的KF在产品开发设计过程中的应用。  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