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   32532篇
  免费   3825篇
  国内免费   2865篇
电工技术   3522篇
技术理论   1篇
综合类   4334篇
化学工业   1651篇
金属工艺   786篇
机械仪表   2741篇
建筑科学   1007篇
矿业工程   570篇
能源动力   892篇
轻工业   1238篇
水利工程   758篇
石油天然气   674篇
武器工业   445篇
无线电   2611篇
一般工业技术   2628篇
冶金工业   524篇
原子能技术   115篇
自动化技术   14725篇
  2024年   112篇
  2023年   328篇
  2022年   688篇
  2021年   806篇
  2020年   853篇
  2019年   869篇
  2018年   739篇
  2017年   973篇
  2016年   1125篇
  2015年   1316篇
  2014年   1796篇
  2013年   2340篇
  2012年   2161篇
  2011年   2351篇
  2010年   1911篇
  2009年   2107篇
  2008年   2312篇
  2007年   2556篇
  2006年   2273篇
  2005年   1902篇
  2004年   1640篇
  2003年   1339篇
  2002年   1160篇
  2001年   935篇
  2000年   838篇
  1999年   625篇
  1998年   493篇
  1997年   451篇
  1996年   363篇
  1995年   289篇
  1994年   272篇
  1993年   201篇
  1992年   189篇
  1991年   155篇
  1990年   115篇
  1989年   102篇
  1988年   103篇
  1987年   59篇
  1986年   55篇
  1985年   38篇
  1984年   52篇
  1983年   30篇
  1982年   36篇
  1981年   23篇
  1980年   24篇
  1979年   29篇
  1978年   11篇
  1977年   21篇
  1976年   14篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
861.
862.
讨论了点阵式液晶显示器与8031单片机的接口方法,给出了程序流程图。  相似文献   
863.
马尔科夫排队过程是马尔科夫决策规划的一个重要应用。本文研究将一般的排队系统转化为马尔科夫排队过程,因而可以利用马尔科夫决策规划的求值运算来求解。本文着重介绍了顾客逐一的接受服务和顾客成批的接受服务两种最主要类型并计算给出相应的结果。  相似文献   
864.
用于PSPICE仿真的IGBT宏模型   总被引:1,自引:0,他引:1  
介绍了一种可用于PSPICE的IGBT宏模型。采用程序设计的方法,将该模型加入到PSPICE的模型库中,并由相关测试电路对此模型进行仿真测试。该模型的仿真值与实际器件测试值相比,无论是DC特性还是开关特性均吻合较好,表明该模型可用于工程CAD中。  相似文献   
865.
This paper addresses the feature sequencing problem in the Rapid Design System (RDS). The RDS is a feature-based design system that integrates product design and process planning. An important issue in feature-based process planning for machined parts is the order in which material is removed to form the resultant part. The order, or sequence, is partially dependent on the geometric relationships between features. The sequence affects the safety, the time it takes to machine the part, and the quality of the finished part. The sequence of material removal depends on two types of relations between features: (1) intersections and (2) interfeature associations. Both types of relations compound the search for an optimal sequence of material removal. Therefore, the research problem has been the discovery and development of a genetic algorithm (GA) that efficiently searches the solution space for all possible sequences and identifies the best sequences in terms of safety, time and quality.  相似文献   
866.
867.
型构兼容的继承及其语义   总被引:1,自引:0,他引:1  
本文揭示了在面向对象程序设计语言中,若劲旅子类重定义其继承的分类方法以发迹这些方法的规约,并且采用类似于Smaltalk-80中的继承机制的语义,将导致封将与继承之间的一个新总是为此,本文提出了一种新的继承机制-型构兼容的继承,以代替传统的增量继承。型构兼容的继承是一种灵活的代码复用机制,并且能够充分支持封装。  相似文献   
868.
In nature the genotype of many organisms exhibits diploidy, i.e., it includes two copies of every gene. In this paper we describe the results of simulations comparing the behavior of haploid and diploid populations of ecological neural networks living in both fixed and changing environments. We show that diploid genotypes create more variability in fitness in the population than haploid genotypes and buffer better environmental change; as a consequence, if one wants to obtain good results for both average and peak fitness in a single population one should choose a diploid population with an appropriate mutation rate. Some results of our simulations parallel biological findings.  相似文献   
869.
A semantics of introspection in a reflective prototype-based language   总被引:1,自引:0,他引:1  
In Malenfant et al. [19], we have described a reflective model for a prototype-based language based on thelookup o apply reflective introspection protocol. In this paper, we augment our previous protocol by converting it to handle continuations reified as first-class objects. First-class continuations provide much more control over the current computation; during the introspection phase fired by message sending, they make it possible not only to change the behavior of the program for that message but also for the entire future computation. In this paper, we provide this introspection protocol with a formal semantics. This result is obtained by exhibiting a mapping from program configurations to priority rewrite systems (PRS) as well as a mapping from message expressions to ground first-order terms used to query the PRS. Other advantages of this approach are: to ensure the termination of the introspection using the smallest set of formally justified conditions and to provide a clear declarative account of this reflective protocol. The PRS also appears as a meta-level to the base language, independent of the implementation, but from which we derive fundamental clues to obtain an efficient language processor. By our new model, we finally highlight the link between reflection in object-oriented languages and the one originally proposed by 3-Lisp [24], although object-orientation provides reusability to reflection, making it easier to use.  相似文献   
870.
A dialectical model of assessing conflicting arguments in legal reasoning   总被引:2,自引:2,他引:0  
Inspired by legal reasoning, this paper presents a formal framework for assessing conflicting arguments. Its use is illustrated with applications to realistic legal examples, and the potential for implementation is discussed. The framework has the form of a logical system for defeasible argumentation. Its language, which is of a logic-programming-like nature, has both weak and explicit negation, and conflicts between arguments are decided with the help of priorities on the rules. An important feature of the system is that these priorities are not fixed, but are themselves defeasibly derived as conclusions within the system. Thus debates on the choice between conflicting arguments can also be modelled.The proof theory of the system is stated in dialectical style, where a proof takes the form of a dialogue between a proponent and an opponent of an argument. An argument is shown to be justified if the proponent can make the opponent run out of moves in whatever way the opponent attacks. Despite this dialectical form, the system reflects a declarative, or relational approach to modelling legal argument. A basic assumption of this paper is that this approach complements two other lines of research in AI and Law, investigations of precedent-based reasoning and the development of procedural, or dialectical models of legal argument.Supported by a research fellowship of the Royal Netherlands Academy of Arts and Sciences, and by Esprit WG 8319 Modelage.  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