全文获取类型
收费全文 | 5174篇 |
免费 | 336篇 |
国内免费 | 501篇 |
专业分类
化学 | 405篇 |
晶体学 | 4篇 |
力学 | 284篇 |
综合类 | 120篇 |
数学 | 4871篇 |
物理学 | 327篇 |
出版年
2024年 | 5篇 |
2023年 | 60篇 |
2022年 | 84篇 |
2021年 | 100篇 |
2020年 | 108篇 |
2019年 | 113篇 |
2018年 | 130篇 |
2017年 | 130篇 |
2016年 | 133篇 |
2015年 | 102篇 |
2014年 | 202篇 |
2013年 | 356篇 |
2012年 | 225篇 |
2011年 | 287篇 |
2010年 | 259篇 |
2009年 | 353篇 |
2008年 | 346篇 |
2007年 | 326篇 |
2006年 | 325篇 |
2005年 | 259篇 |
2004年 | 225篇 |
2003年 | 262篇 |
2002年 | 223篇 |
2001年 | 204篇 |
2000年 | 173篇 |
1999年 | 171篇 |
1998年 | 176篇 |
1997年 | 153篇 |
1996年 | 91篇 |
1995年 | 68篇 |
1994年 | 55篇 |
1993年 | 48篇 |
1992年 | 36篇 |
1991年 | 25篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 12篇 |
1982年 | 21篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 3篇 |
排序方式: 共有6011条查询结果,搜索用时 15 毫秒
931.
932.
933.
《Applied Mathematical Modelling》2014,38(9-10):2543-2557
In this study a generated admissible order between interval-valued intuitionistic uncertain linguistic numbers using two continuous functions is introduced. Then, two interval-valued intuitionistic uncertain linguistic operators called the interval-valued intuitionistic uncertain linguistic Choquet averaging (IVIULCA) operator and the interval-valued intuitionistic uncertain linguistic Choquet geometric mean (IVIULCGM) operator are defined, which consider the interactive characteristics among elements in a set. In order to overall reflect the correlations between them, we further define the generalized Shapley interval-valued intuitionistic uncertain linguistic Choquet averaging (GS-IVIULCA) operator and the generalized Shapley interval-valued intuitionistic uncertain linguistic Choquet geometric mean (GS-IVIULCGM) operator. Moreover, if the information about the weights of experts and attributes is incompletely known, the models for the optimal fuzzy measures on expert set and attribute set are established, respectively. Finally, a method to multi-attribute group decision making under interval-valued intuitionistic uncertain linguistic environment is developed, and an example is provided to show the specific application of the developed procedure. 相似文献
934.
The work of the author in measure and integration is based on new inner and outer envelope formations, which replace the traditional Carathéodory outer measure and certain simple suprema and infima. The new formations lead to essential improvements in both the extent and the adequacy of the basic results. However, they did not find an entrance into the recent textbook literature. The present paper seeks to demonstrate their power with the examples of the basic inner and outer extension and representation theorems for set functions and functionals. 相似文献
935.
王永平 《数学的实践与认识》2014,(6)
在语言图Γ(X*)概念的基础上,用新引入的语言竹竿l(X*)和语言竹竿集L(X*)的概念形象地刻画了前缀码与极大前缀码:A是前缀码l(X*)∈L(X*),S_l_((X*))∩A或为单点集或为Φ;A是极大前缀码l(X*)∈L(X*),i)S_(l(X*))∩A或为单点集或为Φ.ii)S_(l(X*))∩A=Φ■u∈S_(l(X*)),■a∈A,ω∈X~+使a=uw. 相似文献
936.
徐远 《数学的实践与认识》2014,(12)
引入了集列的极限运算与二元集运算之间的共轭可交换性的概念,讨论了常见的和重要的集列的极限运算与集代数运算之间所具有的共轭可交换性质,在一般的情形下证明了共轭可交换性是集类的极限运算生成类对集代数运算具有封闭性的一个充分条件,使得集合形式的单调类定理的理论得到了统一的解释,并且证明更简单,思路更清晰,最后还给出了一个新的集合形式的单调类定理. 相似文献
937.
提出国家电网公司在实施设备的检修作业时尽量减少停电时间,以实现电缆线路状态的有效监控的重要意义.分析缩短单点作业时间的末端影响因素.提出三角模糊集、指数模糊集用于权重设置的具体途径,应用OWA算子于因素排序评价数值的加权,并拓展其基本原理和方法,使其对极端评分值有所抑制对中间评分值有所提升.以上海市电力公司检修公司为研究背景,应用直觉模糊集及其IFHA集成方法于缩短单点作业时间的末端影响因素评价指标排序,并得出u_≥u_≥u_1u_4u_6≥u_2u_3的结论. 相似文献
938.
A dual hesitant fuzzy set (DHFS) consists of two parts, that is, the membership hesitancy function and the nonmembership hesitancy function, supporting a more exemplary and flexible access to assign values for each element in the domain, and can handle two kinds of hesitancy in this situation. It can be considered as a powerful tool to express uncertain information in the process of group decision making. Therefore, we propose a correlation coefficient between DHFSs as a new extension of existing correlation coefficients for hesitant fuzzy sets and intuitionistic fuzzy sets and apply it to multiple attribute decision making under dual hesitant fuzzy environments. Through the weighted correlation coefficient between each alternative and the ideal alternative, the ranking order of all alternatives can be determined and the best alternative can be easily identified as well. Finally, a practical example of investment alternatives is given to demonstrate the practicality and effectiveness of the developed approach. 相似文献
939.
Devika Kannan Ana Beatriz Lopes de Sousa Jabbour Charbel José Chiappetta Jabbour 《European Journal of Operational Research》2014
Due to an increased awareness and significant environmental pressures from various stakeholders, companies have begun to realize the significance of incorporating green practices into their daily activities. This paper proposes a framework using Fuzzy TOPSIS to select green suppliers for a Brazilian electronics company; our framework is built on the criteria of green supply chain management (GSCM) practices. An empirical analysis is made, and the data are collected from a set of 12 available suppliers. We use a fuzzy TOPSIS approach to rank the suppliers, and the results of the proposed framework are compared with the ranks obtained by both the geometric mean and the graded mean methods of fuzzy TOPSIS methodology. Then a Spearman rank correlation coefficient is used to find the statistical difference between the ranks obtained by the three methods. Finally, a sensitivity analysis has been performed to examine the influence of the preferences given by the decision makers for the chosen GSCM practices on the selection of green suppliers. Results indicate that the four dominant criteria are Commitment of senior management to GSCM; Product designs that reduce, reuse, recycle, or reclaim materials, components, or energy; Compliance with legal environmental requirements and auditing programs; and Product designs that avoid or reduce toxic or hazardous material use. 相似文献
940.
主要讨论属性间具有关联性的条件下犹豫模糊多属性决策问题.首先,基于gλ模糊测度,Shapley值和Choquet积分,定义了两种犹豫模糊信息集成算子:AHFGSCgλ算子和GHFGSCgλ算子.然后,讨论了这些算子的一些性质.最后通过一个实例来说明算子的可行性和有效性. 相似文献