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   45318篇
  免费   3960篇
  国内免费   3755篇
电工技术   3813篇
技术理论   5篇
综合类   3160篇
化学工业   2573篇
金属工艺   395篇
机械仪表   1986篇
建筑科学   1713篇
矿业工程   322篇
能源动力   1394篇
轻工业   512篇
水利工程   365篇
石油天然气   263篇
武器工业   240篇
无线电   4383篇
一般工业技术   3244篇
冶金工业   1005篇
原子能技术   180篇
自动化技术   27480篇
  2024年   179篇
  2023年   661篇
  2022年   553篇
  2021年   840篇
  2020年   1154篇
  2019年   1183篇
  2018年   1106篇
  2017年   1549篇
  2016年   1695篇
  2015年   1613篇
  2014年   2755篇
  2013年   3874篇
  2012年   2573篇
  2011年   3079篇
  2010年   2374篇
  2009年   2747篇
  2008年   2905篇
  2007年   3030篇
  2006年   2511篇
  2005年   2242篇
  2004年   1809篇
  2003年   1603篇
  2002年   1356篇
  2001年   1058篇
  2000年   1030篇
  1999年   933篇
  1998年   819篇
  1997年   721篇
  1996年   659篇
  1995年   564篇
  1994年   504篇
  1993年   485篇
  1992年   376篇
  1991年   356篇
  1990年   279篇
  1989年   217篇
  1988年   187篇
  1987年   167篇
  1986年   137篇
  1985年   181篇
  1984年   187篇
  1983年   167篇
  1982年   147篇
  1981年   96篇
  1980年   71篇
  1979年   86篇
  1978年   61篇
  1977年   67篇
  1976年   19篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
The aim of this paper is to assess the state-of-the-art in the Decision Support Systems (DSS) field from both a research and a practice perspective. Three main dimensions of DSS research and practice are addressed: 1) supporting human decision-making processes, 2) integrating DSS into the organizational context, and 3) identifying new application domains. The related analysis and discussion provides a better understanding of past developments in the DSS field and insights into future evolution patterns.  相似文献   
82.
1 IntroductionSince 1 990 ,chaoticsynchronization[1~ 4] andchaoticcontrolling[5~6] havereceivedagreatdealofattention[7~1 1 ] ,andchaoticsynchronizationisaphenomenonofinterestinfieldsfromelectronicstocommunication[1 2 ] ,andfrombiophysicstoneuro science[1 3] .Ifchaoticsync…  相似文献   
83.
跟踪系统中跟踪器延迟的自适应预测补偿方法   总被引:13,自引:4,他引:9  
跟踪系统中跟踪器的延迟会对系统的稳定性和跟踪精度产生不利影响。为此以典型Ⅱ型系统为例,理论上定理地分析了跟踪器延迟对跟踪系统的影响,并提出了将采用LMS算法和横向滤波器结构的自适应滤波器用于延迟预测补偿的方法。仿真结果验证了方法的有效性。  相似文献   
84.
This paper introduces results on placement and communications minimization for systems of affine recurrence equations. We show how to classify the dependences according to the number and nature of communications they may result in. We give both communication-free conditions and conditions for an efficient use of broadcast or neighbor-to-neighbor communication primitives. Since the dependences of a problem can generally not be all communication-free, we finally introduce a heuristic to globally minimize the communications based on the classification of dependences.  相似文献   
85.
线性时变系统的区间稳定性与鲁棒稳定性   总被引:7,自引:0,他引:7  
本文应用向量比较定理研究线性时变系统的区间稳定性和具非线性时变摄动的线性时变系统的鲁棒稳定性,所得的新结果包含文献的一些主要结果作为特例,本文的研究方法说明向量比较方法是分析区间稳定性和鲁棒稳定性的一种自然而有力的工具。  相似文献   
86.
87.
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   
88.
In executing tasks involving intelligent information processing, the human brain performs better than the digital computer. The human brain derives its power from a large number [O(1011)] of neurons which are interconnected by a dense interconnection network [O(105) connections per neuron]. Artificial neural network (ANN) paradigms adopt the structure of the brain to try to emulate the intelligent information processing methods of the brain. ANN techniques are being employed to solve problems in areas such as pattern recognition, and robotic processing. Simulation of ANNs involves implementation of large number of neurons and a massive interconnection network. In this paper, we discuss various simulation models of ANNs and their implementation on distributed memory systems. Our investigations reveal that communication-efficient networks of distributed memory systems perform better than other topologies in implementing ANNs.  相似文献   
89.
ADS expert     
ADS Expert is an integrated system that (a) provides suggestions about suitable optimization algorithms for a particular structural optimization problem, (b) it offers explanations and guide lines, in the form of hypertext, that refer to the optimization strategy, optimizer and one dimensional search method, (c) it produces the required gradients for the objective function and the constraints using symbolic differentiation, (d) establishes a direct linking with ADS routines and (e) it monitors the evolution of the optimization process. The system can be used as an educational tool for structural optimization and as an efficient integrated system for small to medium size optimization problems for which the objective function and the constraints are given in the form of explicit functions of the design variables. The system is a Windows application and runs quite satisfactorily on PCs.  相似文献   
90.
Flexible manufacturing systems (FMSs) are a class of automated systems that can be used to improve productivity in batch manufacturing. Four stages of decision making have been defined for an FMS—the design, planning, scheduling, and control stages. This research focuses on the planning stage, and specifically in the area of scheduling batches of parts through the system.The literature to date on the FMS planning stage has mostly focused on the machine grouping, tool loading, and parttype selection problems. Our research carries the literature a step further by addressing the problem of scheduling batches of parts. Due to the use of serial-access material-handling systems in many FMSs, the batch-scheduling problem is modeled for a flexible flow system (FFS). This model explicitly accounts for setup times between batches that are dependent on their processing sequence.A heuristic procedure is developed for this batch-scheduling problem—the Maximum Savings (MS) heuristic. The MS heuristic is based upon the savings in time associated with a particular sequence and selecting the one with the maximum savings. It uses a two-phase method, with the savings being calculated in phase I, while a branch-and-bound procedure is employed to seek the best heuristic solution in phase II. Extensive computational results are provided for a wide variety of problems. The results show that the MS heuristic provides good-quality solutions.  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