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   4364篇
  免费   463篇
  国内免费   411篇
电工技术   188篇
综合类   398篇
化学工业   42篇
金属工艺   73篇
机械仪表   438篇
建筑科学   73篇
矿业工程   44篇
能源动力   21篇
轻工业   28篇
水利工程   25篇
石油天然气   12篇
武器工业   68篇
无线电   225篇
一般工业技术   179篇
冶金工业   245篇
原子能技术   5篇
自动化技术   3174篇
  2024年   14篇
  2023年   43篇
  2022年   81篇
  2021年   80篇
  2020年   68篇
  2019年   72篇
  2018年   61篇
  2017年   64篇
  2016年   102篇
  2015年   129篇
  2014年   181篇
  2013年   204篇
  2012年   219篇
  2011年   237篇
  2010年   219篇
  2009年   269篇
  2008年   312篇
  2007年   309篇
  2006年   360篇
  2005年   308篇
  2004年   265篇
  2003年   252篇
  2002年   209篇
  2001年   174篇
  2000年   154篇
  1999年   122篇
  1998年   122篇
  1997年   94篇
  1996年   88篇
  1995年   75篇
  1994年   74篇
  1993年   62篇
  1992年   52篇
  1991年   49篇
  1990年   26篇
  1989年   30篇
  1988年   19篇
  1987年   12篇
  1986年   7篇
  1985年   3篇
  1983年   2篇
  1979年   2篇
  1975年   2篇
  1965年   1篇
  1964年   1篇
  1962年   2篇
  1961年   2篇
  1959年   1篇
  1957年   1篇
  1955年   1篇
排序方式: 共有5238条查询结果,搜索用时 12 毫秒
31.
A novel approach to characterise the model prediction errors using a Gaussian mixture model is proposed. The motivation for this work lies behind many data models that are developed through prediction error minimisation with the assumption of a normal noise distribution. When the noise is non-normal, which may often be the case in complicated data modelling scenarios, the model prediction errors may contain rich information, which can be further exploited for model refinement and improvement. The key contents presented in this paper include: choosing the relevant variables to form the error data, optimising the number of Gaussian components required for the error data modelling, and fitting the Gaussian mixture parameters using an expectation-maximisation algorithm. Application of the proposed method for further model improvement, within the framework of hybrid deterministic/stochastic modelling, is also discussed. Preliminary results on the real industrial Charpy impact energy data for heat-treated steels show its effectiveness for model error characterisation, and the potential for model performance improvement in terms of prediction accuracy as well as providing accurate prediction confidence intervals.  相似文献   
32.
全面分析了目前知识处理系统所存在的弊病,提出了下一代语义激活系统,探讨了新一代知识系统所应提供的服务;并将之运用于图形处理系统,阐明了图形数据从统一表示到有效存储、建模、再现和检索等一系列智能处理过程;进而提出了图形信息的语义表示和智能推理模型.  相似文献   
33.
在产品设计规则和计算式中,常存在一些只能在某一范围内取值的待定系数(设为a,且a∈[aL,aH]).a的取值通常受到多种因素的影响和约束,而这种约束往往带有模糊性.为此,首先根据设计规则中各种影响因素对a的模糊约束关系,分别构造两者的备择集以及备择集元素在其论域上的模糊集合,然后基于模糊综合决策方法来确定a.本方法剔除了以往在解决这一问题时,由人来决定a取值的主观性,适用于产品的智能化设计.  相似文献   
34.
35.
Artificial argument assistants for defeasible argumentation   总被引:3,自引:0,他引:3  
Bart Verheij   《Artificial Intelligence》2003,150(1-2):291-324
The present paper discusses experimental argument assistance tools. In contrast with automated reasoning tools, the objective is not to replace reasoning, but to guide the user's production of arguments. Two systems are presented, and based on . The focus is on defeasible argumentation with an eye on the law. Argument assistants for defeasible argumentation naturally correspond to a view of the application of law as dialectical theory construction. The experiments provide insights into the design of argument assistants, and show the pros and cons of different ways of representing argumentative data. The development of the argumentation theories underlying the systems has culminated in the logical system that formalizes the interpretation of prima facie justified assumptions. introduces an innovative use of conditionals expressing support and attack. This allows the expression of warrants for support and attack, making it a transparent and flexible system of defeasible argumentation.  相似文献   
36.
In order to represent legal knowledge adequately, it is vital to create a formal device that can freely construct an individual concept directly from a predicate expression. For this purpose, a Compound Predicate Formula (CPF) is formulated for use in legal expert systems. In this paper, we willattempt to explain the nature of CPFs by rigorous logical foundation, i.e., establishing their syntax and semantics precisely through the use of appropriate examples. We note the advantages of our system over other such systems and discuss the significance of CPFs with regard to the formalization of legal reasonings using examples from the United Nations Convention for the International Sale of Goods.  相似文献   
37.
Signed Systems for Paraconsistent Reasoning   总被引:3,自引:0,他引:3  
We present a novel approach to paraconsistent reasoning, that is, to reasoning from inconsistent information. The basic idea is the following. We transform an inconsistent theory into a consistent one by renaming all literals occurring in the theory. Then, we restore some of the original contents of the theory by introducing progressively formal equivalences linking the original literals to their renamings. This is done as long as consistency is preserved. The restoration of the original contents of the theory is done by appeal to default logic. The overall approach provides us with a family of paraconsistent consequence relations.Our approach is semantical because it works at the level of the propositions; it deals with the semantical link between a proposition and its negation. The approach is therefore independent of the combination of the connectives that are actually applied to the propositions in order to form entire formulas.  相似文献   
38.
Knowledge-based computing, in general, suffers from an inherent open-endedness that precludes its application in time-bounded domains where an answer must be computed within a stipulated time limit. We examine a two-way improvement of the shortcomings: a knowledge representation scheme that provides easy access to relevant knowledge and thereby reduces search time, and a reasoning scheme that is algorithmic in nature and thus makes computational requirements meaningfully estimable.In this work, we offer a cache-based architecture that is capable of both storing knowledge in different formats (e.g. rules, cases), and invoking an appropriate reasoning scheme to fit the available computing time. The cache helps in retrieving the most relevant pieces of knowledge (not only exact matches) required for solving a given problem. This cache relies on a reasoning tactic, knowledge interpolation, that can generate a solution from two near-matches in an algorithmic way, to generate time-bounded solutions. We illustrate the design of such a cache for solving resource allocation problems in the domain of shortwave radio transmission and evaluate its performance in observing imposed temporal bounds.  相似文献   
39.
经典的插值理论针对一维稀疏规则库的条件,提出了各种不同的插值方法,取得了很多很好的经验.但对多维稀疏规则条件的近似推理,研究很少,仅有的几种插值方法,存在着难以保证推理结果的凸性和正规性等问题.为了在多维稀疏规则条件下能得到好的插值推理结果。提出了一种基于几何相似的插值推理方法.该方法能较好地保证推理结果隶属函数的凸性和正规性,为智能系统中的模糊推理提供了一个十分有用的工具.  相似文献   
40.
为快速有效地实现案例推理,提出了基于多EBP神经网的案例匹配技术,设计了改进的德尔菲法来确定输出样本集.与传统的最邻近法的结果相比,对于复杂系统,该技术能够提高案例匹配的精确性,更适于解决案例属性权重难以确定或存在着耦合与非线性关系的问题.  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