全文获取类型
收费全文 | 871篇 |
免费 | 30篇 |
国内免费 | 32篇 |
专业分类
化学 | 4篇 |
力学 | 18篇 |
综合类 | 11篇 |
数学 | 893篇 |
物理学 | 7篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 22篇 |
2013年 | 48篇 |
2012年 | 76篇 |
2011年 | 22篇 |
2010年 | 26篇 |
2009年 | 42篇 |
2008年 | 42篇 |
2007年 | 47篇 |
2006年 | 49篇 |
2005年 | 48篇 |
2004年 | 31篇 |
2003年 | 28篇 |
2002年 | 29篇 |
2001年 | 36篇 |
2000年 | 25篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 17篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有933条查询结果,搜索用时 46 毫秒
111.
Hans U. Gerber 《Insurance: Mathematics and Economics》1984,3(2):97-100
The classical theory is adapted to the situation where the risk exchange of n insurance companies is an exchange of payments that belong to a certain linear class of random variables, for example the payments corresponding to certain layers of the aggregate claims. Similarly, a price equilibrium is considered, where the companies can purchase payments of a linear class. An example is the case where each company buys proportional coverage for its own claims and sells proportional coverage for the claims of the other companies. 相似文献
112.
A class of nondifferentiable control problems 总被引:2,自引:0,他引:2
S. Chandra B. D. Craven I. Husain 《Journal of Optimization Theory and Applications》1988,56(2):227-243
Optimality conditions and duality results are obtained for a class of control problems having a nondifferentiable term in the integrand of the objective functional. These results generalize many well-known results in optimal control theory involving differentiable functions, and also provide a relationship with certain nondifferentiable mathematical programming problems. Some extensions concerning the unified treatment of optimal control theory and continuous programming are also mentioned. Finally, a control problem containing an arbitrary norm, along with its appropriate norm, is given. 相似文献
113.
Preface to topics in data envelopment analysis 总被引:7,自引:0,他引:7
This paper serves as an introduction to a series of three papers which are directed to different aspects of DEA (Data Envelopment Analysis) as follows: (1) uses and extensions of window analyses' to study DEA efficiency measures with an illustrative applications to maintenance activities for U.S. Air Force fighter wings, (2) a comparison of DEA and regression approaches to identifying and estimating, sources of inefficiency by means of artificially generated data, and (3) an extension of ordinary (linear programming) sensitivity analyses to deal with special features that require attention in DEA. Background is supplied in this introductory paper with accompanying proofs and explanations to facilitate understanding of what DEA provides in the way of underpinning for the papers that follow. An attempt is made to bring readers abreast of recent progress in DEA research and uses. A synoptic history is presented along with brief references to related work, and problems requiring attention are also indicated and possible research approaches also suggested.This research was partly supported by the National Science Foundation and USARI Contract MDA 903-83-K0312, with the Center for Cybernetic Studies, the University of Texas at Austin. It was also partly supported by the IC2 Institute at the University of Texas at Austin. Reproduction in whole or in part is permitted for any purpose of the U.S. Government. 相似文献
114.
We study the Pareto optimal equilibria payoffs of the non-cooperative game associated with the cost spanning tree problem.
We give two characterisations of these payoffs: one based on the tree they induce and another based on the strategies played
by agents. Moreover, an algorithm for computing all these payoffs is provided. 相似文献
115.
In this article, we consider bilevel optimization problems with discrete lower level and continuous upper level problems. Taking into account both approaches (optimistic and pessimistic) which have been developed in the literature to deal with this type of problem, we derive some conditions for the existence of solutions. In the case where the lower level is a parametric linear problem, the bilevel problem is transformed into a continuous one. After that, we are able to discuss local optimality conditions using tools of variational analysis for each of the different approaches. Finally, we consider a simple application of our results namely the bilevel programming problem with the minimum spanning tree problem in the lower level. 相似文献
116.
Blocking is often used to reduce known variability in designed experiments by collecting together homogeneous experimental units. A common modeling assumption for such experiments is that responses from units within a block are dependent. Accounting for such dependencies in both the design of the experiment and the modeling of the resulting data when the response is not normally distributed can be challenging, particularly in terms of the computation required to find an optimal design. The application of copulas and marginal modeling provides a computationally efficient approach for estimating population‐average treatment effects. Motivated by an experiment from materials testing, we develop and demonstrate designs with blocks of size two using copula models. Such designs are also important in applications ranging from microarray experiments to experiments on human eyes or limbs with naturally occurring blocks of size two. We present a methodology for design selection, make comparisons to existing approaches in the literature, and assess the robustness of the designs to modeling assumptions. 相似文献
117.
利用K-方向导数,给出了一类存在性更为广泛的广义凸函数.即广义一致K-(F,α,ρ,d)-I型凸函数,进而讨论了涉及这些新广义凸性的一类多目标半无限规划的最优性条件。 相似文献
118.
This work develops asymptotically optimal dividend policies to maximize the expected present value of dividends until ruin.Compound Poisson processes with regime switching are used to model the surplus and the switching(a continuous-time controlled Markov chain) represents random environment and other economic conditions.Assuming the switching to be fast varying together with suitable conditions,it is shown that the system has a limit that is an average with respect to the invariant measure of a related Markov chain.Under simple conditions,the optimal policy of the limit dividend strategy is a threshold policy.Using the optimal policy of the limit system as a guide,feedback control for the original surplus is then developed.It is demonstrated that the constructed dividend policy is asymptotically optimal. 相似文献
119.
No-gap optimality conditions for an optimal control problem with pointwise control-state constraints
An optimal control problem with pointwise mixed constraints of the instationary three-dimensional Navier–Stokes–Voigt equations is considered. We derive second-order optimality conditions and show that there is no gap between second-order necessary optimality conditions and second-order sufficient optimality conditions. In addition, the second-order sufficient optimality conditions for the problem where the objective functional does not contain a Tikhonov regularization term are also discussed. 相似文献
120.
Xiaoqi Yang 《Numerical Functional Analysis & Optimization》2013,34(5-6):621-632
Second-order necessary conditions for inequality and equality constrained C1, 1 optimization problems are derived. A constraint qualification condition which uses the recent generalized second-order directional derivative is employed to obtain these conditions. Various second-order sufficient conditions are given under appropriate conditions on the generalized second-order directional derivative in a neighborhood of a given point. An application of the secondorder conditions to a new class of nonsmooth C1, 1 optimization problems with infinitely many constraints is presented. 相似文献