全文获取类型
收费全文 | 2087篇 |
免费 | 337篇 |
国内免费 | 74篇 |
专业分类
化学 | 75篇 |
晶体学 | 1篇 |
力学 | 156篇 |
综合类 | 112篇 |
数学 | 1839篇 |
物理学 | 315篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 51篇 |
2021年 | 96篇 |
2020年 | 39篇 |
2019年 | 36篇 |
2018年 | 30篇 |
2017年 | 97篇 |
2016年 | 130篇 |
2015年 | 69篇 |
2014年 | 167篇 |
2013年 | 124篇 |
2012年 | 127篇 |
2011年 | 128篇 |
2010年 | 116篇 |
2009年 | 138篇 |
2008年 | 112篇 |
2007年 | 125篇 |
2006年 | 118篇 |
2005年 | 118篇 |
2004年 | 91篇 |
2003年 | 95篇 |
2002年 | 79篇 |
2001年 | 47篇 |
2000年 | 43篇 |
1999年 | 29篇 |
1998年 | 48篇 |
1997年 | 26篇 |
1996年 | 30篇 |
1995年 | 22篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 23篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 23篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有2498条查询结果,搜索用时 31 毫秒
101.
Tasuku?ToyonagaEmail author Takesh?Itoh Hiroaki?Ishii 《Fuzzy Optimization and Decision Making》2005,4(1):51-69
The main purpose of this paper is to present a crop planning problem for agricultural management under uncertainty. It is significant that agricultural managers assign their limited farmlands to cultivation of which crops in a season. This planning is called the crop planning problem and influences their incomes for the season. Usually, the crop planning problem is formulated as a linear programming problem. But there are many uncertain factors in agricultural problems, so future profits for crops are not certain values. A linear programming model with constant profit coefficients may not reflect the environment of decision making properly. Therefore, we propose a model of crop planning with fuzzy profit coefficients, and an effective solution procedure for the model. Furthermore, we extend this fuzzy model, setting the profit coefficients as discrete randomized fuzzy numbers. We show concrete optimal solutions for each models. 相似文献
102.
船舶碰撞危险度模型的构建 总被引:6,自引:0,他引:6
运用模糊数学的综合评判理论,把会遇中目标船的DCPA、TCPA两船距离、相对方位、船速比5个因素作为基本评判参数,建立碰撞危险度的评价模型.而将其它因素,如航行区域状况、能见度情况和船舶的操纵性能等,作为对上述因素的危险隶属度函数的修正加以考虑.引入了船舶领域、动界等概念,以对来船构成的本船危险度进行客观有效地评价,为安全避碰提供合理依据. 相似文献
103.
Volker Stix 《Computational Optimization and Applications》2004,27(2):173-186
Clustering applications dealing with perception based or biased data lead to models with non-disjunct clusters. There, objects to be clustered are allowed to belong to several clusters at the same time which results in a fuzzy clustering. It can be shown that this is equivalent to searching all maximal cliques in dynamic graphs like G
t = (V,E
t), where E
t – 1 E
t, t = 1,...,T; E
0 = . In this article algorithms are provided to track all maximal cliques in a fully dynamic graph. 相似文献
104.
模糊最短路问题在许多领域有着广泛的应用,研究这一问题具有重要意义。根据多准则决策理论求非被支配路径集合,求最大效用模糊最短路以及利用模糊数排序方法求模糊最短路是常用的三种研究方法,本文利用OERI排序原理,使网络模糊边长具有线性可加性,对具有三角模糊数边权的网络给出了一种标号算法,该算法简单高效,且易于在计算机上实现,算法的时间复杂度为O(n^2)。 相似文献
105.
In Knowledge Discovery in Databases (KDD)/Data Mining literature, interestingness measures are used to rank rules according to the interest a particular rule is expected to evoke. In this paper, we introduce an aspect of subjective interestingness called item-relatedness. Relatedness is a consequence of relationships that exist between items in a domain. Association rules containing unrelated or weakly related items are interesting since the co-occurrence of such items is unexpected. Item-Relatedness helps in ranking association rules on the basis of one kind of subjective unexpectedness. We identify three types of item-relatedness – captured in the structure of a fuzzy taxonomy (an extension of the classical concept hierarchy tree). An item-relatedness measure for describing relatedness between two items is developed by combining these three types. Efficacy of this measure is illustrated with the help of a sample taxonomy. We discuss three mechanisms for extending this measure from a two-item set to an association rule consisting of a set of more than two items. These mechanisms utilize the relatedness of item-pairs and other aspects of an association rule, namely its structure, distribution of items and item-pairs. We compare our approach with another method from recent literature. 相似文献
106.
Manuel Tarrazo 《Fuzzy Optimization and Decision Making》2004,3(3):227-254
Prolegomenon means something said in advance of something else. In this study, we posit that part of the work by Arthur Schopenhauer (1788–1860) can be thought of as a prolegomenon to the existing concept of fuzziness. His epistemic framework offers a comprehensive and surprisingly modern framework to study individual decision making and suggests a bridgeway from the Kantian program into the concept of fuzziness, which may have had its second prolegomenon in the work by Frege, Russell, Wittgenstein, Peirce and Black. In this context, Zadeh's seminal contribution can be regarded as the logical consequence of the Kant-Schopenhauer representation framework. 相似文献
107.
多级模糊综合评判在高校教师考评中的应用 总被引:3,自引:0,他引:3
介绍了模糊综合评判的数学模型.并将二级模糊综合评判用于高校教师的考评,为客观地评价教师提供了一种定量的、科学的方法. 相似文献
108.
高校人力资源管理中的模糊综合评判 总被引:6,自引:0,他引:6
人力资源管理是高校管理的重要组成部分。本简要介绍了高校人力资源的状况,讨论了模糊综合评判理论在人力资源管理中的应用。 相似文献
109.
建立模糊诊断矩阵的一种新方法 总被引:1,自引:0,他引:1
王司 《数学的实践与认识》2001,31(4):391-393
本文首先提出了一个新的模糊逻辑算子——模糊加权综合算子“#”,进而给出建立模糊诊断矩阵的新方法——网络法 ,并给出了相应的算法 相似文献
110.
Ozer TALO Feyzi BASAR 《数学学报(英文版)》2008,24(7):1205-1212
Recently, the space bvp of real or complex numbers consisting of all sequences whose differences are in the space lp has been studied by Basar, Altay [Ukrainian Math. J. 55(1)(2003), 136-147], where 1 ≤ p ≤ ∞. The main purpose of the present paper is to introduce the space bvp(F) of sequences of p-bounded variation of fuzzy numbers. Moreover, it is proved that the space bvp(F) includes the space lp(F) and also shown that the spaces bvp(F) and lp(F) axe isomorphic for 1 ≤ p ≤∞. Furthermore, some inclusion relations have been given. 相似文献