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   53172篇
  免费   5186篇
  国内免费   4948篇
电工技术   4721篇
技术理论   5篇
综合类   5159篇
化学工业   3267篇
金属工艺   465篇
机械仪表   2427篇
建筑科学   3086篇
矿业工程   381篇
能源动力   1730篇
轻工业   610篇
水利工程   714篇
石油天然气   504篇
武器工业   395篇
无线电   5101篇
一般工业技术   5448篇
冶金工业   1080篇
原子能技术   249篇
自动化技术   27964篇
  2024年   240篇
  2023年   810篇
  2022年   747篇
  2021年   1074篇
  2020年   1514篇
  2019年   1568篇
  2018年   1476篇
  2017年   1944篇
  2016年   2153篇
  2015年   1946篇
  2014年   3053篇
  2013年   4581篇
  2012年   2993篇
  2011年   3418篇
  2010年   2529篇
  2009年   3105篇
  2008年   3162篇
  2007年   3335篇
  2006年   2862篇
  2005年   2585篇
  2004年   2152篇
  2003年   1950篇
  2002年   1752篇
  2001年   1486篇
  2000年   1459篇
  1999年   1248篇
  1998年   1081篇
  1997年   996篇
  1996年   856篇
  1995年   747篇
  1994年   654篇
  1993年   585篇
  1992年   473篇
  1991年   434篇
  1990年   340篇
  1989年   261篇
  1988年   216篇
  1987年   176篇
  1986年   151篇
  1985年   185篇
  1984年   193篇
  1983年   172篇
  1982年   151篇
  1981年   100篇
  1980年   77篇
  1979年   90篇
  1978年   67篇
  1977年   68篇
  1976年   20篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
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   
52.
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   
53.
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   
54.
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   
55.
56.
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   
57.
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   
58.
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   
59.
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   
60.
针对基于非线性谱分析的故障诊断技术的需要,研究了非线性系统的广义频率响应函数的鲁棒在线建模方 法。首先将次元分析算法应用于Volterra级数模型的辨识,并通过对此算法的修正,得到了一种改进的Volterra系统的鲁 棒辨识算法。对其鲁棒性能进行的分析表明,改进算法的鲁棒抗噪性能被明显提高。在此基础上,提出了一种广义频率响 应函数的两步鲁棒建模新方法。仿真实验表明,该方法具有良好的鲁棒收敛性能,能够有效解决GFRF的在线建模问题。  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