全文获取类型
收费全文 | 3541篇 |
免费 | 170篇 |
国内免费 | 250篇 |
专业分类
化学 | 20篇 |
力学 | 82篇 |
综合类 | 45篇 |
数学 | 3671篇 |
物理学 | 143篇 |
出版年
2023年 | 24篇 |
2022年 | 18篇 |
2021年 | 38篇 |
2020年 | 51篇 |
2019年 | 64篇 |
2018年 | 66篇 |
2017年 | 80篇 |
2016年 | 88篇 |
2015年 | 72篇 |
2014年 | 114篇 |
2013年 | 173篇 |
2012年 | 156篇 |
2011年 | 136篇 |
2010年 | 120篇 |
2009年 | 182篇 |
2008年 | 195篇 |
2007年 | 209篇 |
2006年 | 193篇 |
2005年 | 176篇 |
2004年 | 167篇 |
2003年 | 153篇 |
2002年 | 140篇 |
2001年 | 136篇 |
2000年 | 169篇 |
1999年 | 119篇 |
1998年 | 129篇 |
1997年 | 115篇 |
1996年 | 68篇 |
1995年 | 60篇 |
1994年 | 58篇 |
1993年 | 45篇 |
1992年 | 41篇 |
1991年 | 39篇 |
1990年 | 38篇 |
1989年 | 21篇 |
1988年 | 29篇 |
1987年 | 25篇 |
1986年 | 22篇 |
1985年 | 33篇 |
1984年 | 27篇 |
1983年 | 6篇 |
1982年 | 24篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 24篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 20篇 |
1975年 | 3篇 |
1974年 | 11篇 |
排序方式: 共有3961条查询结果,搜索用时 15 毫秒
51.
52.
Lina Mallozzi 《Operations Research Letters》2007,35(2):151-154
A noncooperative game theoretical approach is considered for the multifacility location problem. It turns out that the facility location game is a potential game in the sense of Monderer and Shapley and some properties of the game are studied. 相似文献
53.
M. Abbad R. El. Azouzi M. El. Kamili 《Mathematical Methods of Operations Research》2006,63(3):461-471
In this paper we consider some properties on prices under flow control in a network that is to be shared by noncooperative users. Each user is faced with an optimization problem which is formulated as the minimization of its own criterion subject to constraint on the flows of the other users. The operating points of the network are the Nash equilibria of the underlying routing game. Our objective is to study the behavior of prices of all users when the network designer needs to allocate capacities to network links. For parallel links topologies, we show that degradation of the performances such as prices will not take place, as well as the users may find it beneficial to improve their requests 相似文献
54.
55.
Pure adaptive search constructs a sequence of points uniformly distributed within a corresponding sequence of nested regions of the feasible space. At any stage, the next point in the sequence is chosen uniformly distributed over the region of feasible space containing all points that are equal or superior in value to the previous points in the sequence. We show that for convex programs the number of iterations required to achieve a given accuracy of solution increases at most linearly in the dimension of the problem. This compares to exponential growth in iterations required for pure random search. 相似文献
56.
In this paper we define two classes of quasiconformal mappings,and study their covering properties by methods of module.We obtain some new results.In the meantime,we give new methods to prove Koebe 1/2 covering theorem on convex conformal mappings. 相似文献
57.
C. Zălinescu 《Mathematical Methods of Operations Research》1991,35(4):291-298
In this paper there is stated a result on sets in ordered linear spaces which can be used to show that some properties of the sets are inherited by their convex hulls under suitable conditions. As applications one gives a characterization of weakly efficient points and a duality result for nonconvex vector optimization problems. 相似文献
58.
A stochastic version of Isaacs's (Ref. 1) game of two cars is dealt with here. In this version, the pursuer, owing to thrust and drag forces, has a variable speed, whereas the evader's speed is constant. Also, the pursuer can maneuver as long as his speed is bounded by some lower and upper limits. The probability of interception, corresponding to optimal (saddle-point) feedback strategies, is computed and serves as a reference for evaluating the performance of four different versions of the proportional navigation pursuit law as well as two other strategies. 相似文献
59.
60.
The sum of the largest eigenvalues of a symmetric matrix is a nonsmooth convex function of the matrix elements. Max characterizations for this sum are established, giving a concise characterization of the subdifferential in terms of a dual matrix. This leads to a very useful characterization of the generalized gradient of the following convex composite function: the sum of the largest eigenvalues of a smooth symmetric matrix-valued function of a set of real parameters. The dual matrix provides the information required to either verify first-order optimality conditions at a point or to generate a descent direction for the eigenvalue sum from that point, splitting a multiple eigenvalue if necessary. Connections with the classical literature on sums of eigenvalues and eigenvalue perturbation theory are discussed. Sums of the largest eigenvalues in the absolute value sense are also addressed.This paper is dedicated to Phil Wolfe on the occasion of his 65th birthday.The work of this author was supported by the National Science Foundation under grants CCR-8802408 and CCR-9101640.The work of this author was supported in part during a visit to Argonne National Laboratory by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department of Energy under contract W-31-109-Eng-38, and in part during a visit to the Courant Institute by the U.S. Department of Energy under Contract DEFG0288ER25053. 相似文献