全文获取类型
收费全文 | 1799篇 |
免费 | 158篇 |
国内免费 | 98篇 |
专业分类
化学 | 176篇 |
晶体学 | 2篇 |
力学 | 95篇 |
综合类 | 4篇 |
数学 | 1497篇 |
物理学 | 281篇 |
出版年
2023年 | 20篇 |
2022年 | 27篇 |
2021年 | 22篇 |
2020年 | 38篇 |
2019年 | 32篇 |
2018年 | 37篇 |
2017年 | 37篇 |
2016年 | 60篇 |
2015年 | 33篇 |
2014年 | 62篇 |
2013年 | 119篇 |
2012年 | 74篇 |
2011年 | 100篇 |
2010年 | 78篇 |
2009年 | 92篇 |
2008年 | 99篇 |
2007年 | 96篇 |
2006年 | 87篇 |
2005年 | 80篇 |
2004年 | 81篇 |
2003年 | 83篇 |
2002年 | 52篇 |
2001年 | 62篇 |
2000年 | 62篇 |
1999年 | 51篇 |
1998年 | 50篇 |
1997年 | 30篇 |
1996年 | 33篇 |
1995年 | 27篇 |
1994年 | 29篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 26篇 |
1990年 | 21篇 |
1989年 | 16篇 |
1988年 | 19篇 |
1987年 | 15篇 |
1986年 | 18篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 2篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 17篇 |
1974年 | 5篇 |
1973年 | 1篇 |
排序方式: 共有2055条查询结果,搜索用时 15 毫秒
141.
M. S. Agranovich 《Functional Analysis and Its Applications》2006,40(4):313-329
In a bounded Lipschitz domain in ?n, we consider a second-order strongly elliptic system with symmetric principal part written in divergent form. We study the Neumann boundary value problem in a generalized variational (or weak) setting using the Lebesgue spaces H p σ (Ω) for solutions, where p can differ from 2 and σ can differ from 1. Using the tools of interpolation theory, we generalize the known theorem on the regularity of solutions, in which p = 2 and {σ ? 1} < 1/2, and the corresponding theorem on the unique solvability of the problem (Savaré, 1998) to p close to 2. We compare this approach with the nonvariational approach accepted in numerous papers of the modern theory of boundary value problems in Lipschitz domains. We discuss the regularity of eigenfunctions of the Dirichlet, Neumann, and Poincaré-Steklov spectral problems. 相似文献
142.
In this note we study uncertainty sequencing situations, i.e., one-machine sequencing situations in which no initial order
is specified. We associate cooperative games with these sequencing situations, study their core, and provide links with the
classic sequencing games introduced by Curiel et al. (Eur J Oper Res 40:344–351, 1989). Moreover, we propose and characterize
two simple cost allocation rules for uncertainty sequencing situations with equal processing times. 相似文献
143.
Definitions of equilibrium in network formation games 总被引:1,自引:0,他引:1
We examine a variety of stability and equilibrium definitions that have been used to study the formation of social networks among a group of players. In particular we compare variations on three types of definitions: those based on a pairwise stability notion, those based on the Nash equilibria of a link formation game, and those based on equilibria of a link formation game where transfers are possible.Bloch is also affiliated with the University of Warwick. 相似文献
144.
Andronikos Paliathanasis 《Mathematical Methods in the Applied Sciences》2020,43(2):716-726
Lie symmetries are applied to classify the source of the magnetic field for the Pulsar equation near to the surface of the neutron star. We find that there are six possible different admitted Lie algebras. We apply the corresponding Lie invariants to reduce the Pulsar equation close to the surface to an ordinary differential equation. This equation is solved either with the use of Lie symmetries or the application of the ARS algorithm for singularity analysis to write the analytic solution as a Laurent expansion. These solutions are called inner solutions. 相似文献
145.
Given a variety , we provide an axiomatization of the class of complex algebras of algebras in . can be obtained effectively from the axiomatization of ; in fact, if this axiomatization is recursively enumerable, then is recursive.
Received January 18, 2000; accepted in final form December 18, 2000. 相似文献
146.
In this paper, we study monopolistic pricing behaviors within a two-way network. In this symbiotic production system, independent decision centers carry out an activity which concurs to the production of different system goods. The players are assumed to know the whole network. Due to this rationality, they try to capture a share of the profit of the firms who sell the system goods to the consumers. These double marginalization behaviors are studied within very general networks. Conditions with ensure existence and uniqueness are discussed. We even provided a complete characterization of an equilibrium. Potential applications are also discussed 相似文献
147.
Cooperative Advertising in a Marketing Channel 总被引:21,自引:0,他引:21
Jørgensen S. Taboubi S. Zaccour G. 《Journal of Optimization Theory and Applications》2001,110(1):145-158
This paper examines dynamic advertising and promotion strategies in a marketing channel where the retailer promotes the manufacturer product and the manufacturer spends on advertising to build a stock of goodwill. We assume that sales depend on goodwill and promotion activities and that there are decreasing marginal returns to goodwill. Two scenarios are studied. First, the manufacturer and retailer determine noncooperatively their respective strategies. Second, the game is played à la Stackelberg with the manufacturer as the leader who supports partially the cost of the promotion activities of the retailer. In both cases, stationary Markovian strategies are characterized. These scenarios are examined also in the absence of decreasing marginal effect of goodwill on sales. The results show that, whether or not the goodwill stock has a decreasing marginal effect on sales, the cooperative advertising program is a coordinating mechanism in the marketing channel, i.e., both players receive higher payoffs. 相似文献
148.
1. IntroductionIn the numerical approximation of PDE, it is often very importals to detect regionswhere the accuracy of the numerical solution is degraded by local singularities of the solutionof the continuous problem such as the singularity near the re-entrant corller. An obviousremedy is to refine the discretization in the critical regions, i.e., to place more gridpointswhere the solution is less regular. The question is how to identify these regions automdticallyand how to determine a goo… 相似文献
149.
ABSTRACT. This paper analyzes a two-stage game, based on the Gordon-Schaefer model of the fishery, to examine the strategic entry-deterring role for effort subsidies in noncooper-ative transboundary fisheries. The game reveals that a country, whose domestic fleet has an effort cost advantage over a rival foreign fleet, may choose to subsidize domestic effort to the point that foreign entry in the fishery becomes unprofitable. Whether the outcome of the game is characterized by foreign entry deterrence or accommodation, and whether it is also characterized by a domestic effort subsidy or a tax, depends on domestic and foreign effort costs and the number of firms in each fleet. The various outcomes of the game analyzed here help to explain the persistence of subsidies in some world fisheries. 相似文献
150.
“无中生有”计的一个博弈模型 总被引:10,自引:3,他引:10
“无中生有”计系《三十六计》中的第七计,本首先给出此计的一个博弈模型,然后由此研究破此计的一个算法。 相似文献