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   2623篇
  免费   22篇
  国内免费   36篇
化学   59篇
力学   54篇
综合类   22篇
数学   2367篇
物理学   179篇
  2024年   2篇
  2023年   10篇
  2022年   12篇
  2021年   11篇
  2020年   32篇
  2019年   14篇
  2018年   18篇
  2017年   33篇
  2016年   39篇
  2015年   32篇
  2014年   110篇
  2013年   135篇
  2012年   141篇
  2011年   168篇
  2010年   109篇
  2009年   212篇
  2008年   141篇
  2007年   186篇
  2006年   147篇
  2005年   102篇
  2004年   81篇
  2003年   67篇
  2002年   75篇
  2001年   113篇
  2000年   82篇
  1999年   68篇
  1998年   67篇
  1997年   53篇
  1996年   53篇
  1995年   43篇
  1994年   11篇
  1993年   18篇
  1992年   14篇
  1991年   12篇
  1990年   10篇
  1989年   11篇
  1988年   8篇
  1987年   2篇
  1986年   7篇
  1985年   50篇
  1984年   49篇
  1983年   20篇
  1982年   38篇
  1981年   32篇
  1980年   24篇
  1979年   15篇
  1978年   3篇
  1976年   1篇
排序方式: 共有2681条查询结果,搜索用时 14 毫秒
181.
洗国荣  陈卓荣 《数学季刊》1997,12(1):104-110
51.IntroductionLetF=[O,1],foranya,beF,definea b=max{a,b},a*b=min{a,b}.Mn(F)standsforthesetofa1lthenthordermatrixesinF,matrixAinMn(F)iscalledFuzzymatrixA.Letrbeanynon-negativeinteger.lnannthordermatrix,exclusiveofthefirstrow,theelementsofeveryotherrowarethee1ementsoftheprecedingrowthatcirculaterightwardr-co1umns.Thisnthordermatrixisannthorderr-circulantFuzzymatrix(alsocalledgenearLizedcirculantFuzzymatrix)-Wecallrthecircu1antindexofr-circulantFuzzymatrix.Inthebooklistedin[1j,thisisgiven:…  相似文献   
182.
In this paper we obtain a finite Hilbert-style axiomatization of the implicationless fragment of the intuitionistic propositional calculus. As a consequence we obtain finite axiomatizations of all structural closure operators on the algebra of {–}-formulas containing this fragment. Mathematics Subject Classification: 03B20, 03B22, 06D15.  相似文献   
183.
In this paper, we get several equivalent conditions of some methods on multidimensional (multicon-ditional) fuzzy reasoning.  相似文献   
184.
Probability distributions associated with several ‘ply’-operators are discussed. These exact distributions are compared with relevant Gaussian approximations.  相似文献   
185.
基于集值统计的模糊神经网络专家系统及其应用   总被引:13,自引:1,他引:12  
建立基于集值统计的模糊神经网络专家评审系统,并应用于科研项目评审工作,实际应用表明该系统是可行的。  相似文献   
186.
Voting algorithms are used to arbitrate between the results of redundant modules in fault-tolerant systems. Inexact majority and weighted average voters have been used in many applications, although both have problems associated with them. Inexact majority voters require an application-specific 'voter threshold’ value to be specified, whereas weighted average voters are unable to produce a benign output when no agreement exists between the voter inputs. Neither voter type is able to cope with uncertainties associated with the voter inputs. This paper introduces a novel voting scheme based on fuzzy set theory. It softens the harsh behaviour of the inexact majority voter in the neighbourhood of the ‘voter threshold’, and handles uncertainty and some multiple error cases in the region defined by the fuzzy input variables. The voter assigns a fuzzy difference value to each pair of voter inputs based on their numerical distance. A set of fuzzy rules then determines a single fuzzy agreeability value for each individual input which describes how well it matches the other inputs. The agreeability of each voter input is then defuzzified to give a weighting value for that input which determines its contribution to the voter output. The weight values are then used in the weighted average algorithm for calculating the voter final output. The voter is experimentally evaluated from the point of view safety and availability, and compared with the inexact majority voter in a Triple Modular Redundant structured framework. The impact of changing some fuzzy variables on the performance of the voter is also investigated. We show that the fuzzy voter gives more correct outputs (higher availability) than the inexact majority voter with small and large errors, less incorrect outputs (higher safety) than the inexact majority voter in the presence of small errors, and less benign outputs than the inexact majority voter. The percentage of the benign outputs of the majority voter that are successfully handled by the fuzzy voter (resulting in correct outputs) is more than the percentage of those that are unsuccessfully resolved by the fuzzy voter (resulting in incorrect outputs). Our results suggest that the fuzzy voter is a viable alternative to a traditional inexact voter in cases where the benefits of a large increase in availability, and a considerable decrease in the number of benign outputs outweighs the cost of a small degradation in the safety performance of the system. The fuzzy voter is also a useful voting algorithm when arbitrating between the responses of dynamic channels of control systems incorporating uncertainties. This is the first reported use of a complete fuzzy voter in the context of fault tolerance.  相似文献   
187.
A novel adaptive algorithm for tracking maneuvering targets is proposed. The algorithm is implemented with fuzzy-controlled current statistic model adaptive filtering and unscented transformation. A fuzzy system allows the filter to tune the magnitude of maximum accelerations to adapt to different target maneuvers, and unscented transformation can effectively handle nonlinear system. A bearing-only tracking scenario simulation results show the proposed algorithm has a robust advantage over a wide range of maneuvers and overcomes the shortcoming of the traditional current statistic model and adaptive filtering algorithm.  相似文献   
188.
Fuzzy信息系统的Rough集理论   总被引:8,自引:2,他引:6  
提出 Fuzzy信息系统的概念 ,建立 fuzzy信息系统上的 Rough集理论 ,给出 Fuzzy信息系统与经典信息系统的关系 ,讨论 Fuzzy信息系统的知识约简问题  相似文献   
189.
可列集合套   总被引:5,自引:0,他引:5  
[1]中给出模糊集的分解定理与表现定理,指出可利用集合套H={H(λ)|λ∈[0,1]}刻化模糊集。本文定义可列集合套H={H(a)|a∈Q},Q是(0,1)的可列稠密子集。相应地给出新的分解定理与表现定理。指出可利用可列集合套刻化的模糊集。  相似文献   
190.
定义了模糊相对熵,基于模糊熵和距离定义了模糊信息差异、拟模糊信息差异,并讨论了模糊信息差异唯一性定理以及模糊信息差异的性质.  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