全文获取类型
收费全文 | 8715篇 |
免费 | 713篇 |
国内免费 | 717篇 |
专业分类
化学 | 264篇 |
晶体学 | 6篇 |
力学 | 409篇 |
综合类 | 204篇 |
数学 | 8703篇 |
物理学 | 559篇 |
出版年
2024年 | 16篇 |
2023年 | 87篇 |
2022年 | 107篇 |
2021年 | 149篇 |
2020年 | 201篇 |
2019年 | 215篇 |
2018年 | 219篇 |
2017年 | 264篇 |
2016年 | 271篇 |
2015年 | 169篇 |
2014年 | 363篇 |
2013年 | 700篇 |
2012年 | 408篇 |
2011年 | 471篇 |
2010年 | 390篇 |
2009年 | 570篇 |
2008年 | 507篇 |
2007年 | 521篇 |
2006年 | 506篇 |
2005年 | 398篇 |
2004年 | 347篇 |
2003年 | 343篇 |
2002年 | 369篇 |
2001年 | 332篇 |
2000年 | 321篇 |
1999年 | 274篇 |
1998年 | 260篇 |
1997年 | 234篇 |
1996年 | 166篇 |
1995年 | 139篇 |
1994年 | 129篇 |
1993年 | 93篇 |
1992年 | 63篇 |
1991年 | 65篇 |
1990年 | 65篇 |
1989年 | 37篇 |
1988年 | 29篇 |
1987年 | 34篇 |
1986年 | 30篇 |
1985年 | 46篇 |
1984年 | 38篇 |
1983年 | 18篇 |
1982年 | 40篇 |
1981年 | 27篇 |
1980年 | 17篇 |
1979年 | 20篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1976年 | 14篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
The large deviation principle (LDP) which has been effectively used in queueing analysis is the sample path LDP, the LDP in a function space endowed with the uniform topology. Chang [5] has shown that in the discrete-time G/D/1 queueing system under the FIFO discipline, the departure process satisfies the sample path LDP if so does the arrival process. In this paper, we consider arrival processes satisfying the LDP in a space of measures endowed with the weak* topology (Lynch and Sethuraman [12]) which holds under a weaker condition. It is shown that in the queueing system mentioned above, the departure processes still satisfies the sample path LDP. Our result thus covers arrival processes which can be ruled out in the work of Chang [5]. The result is then applied to obtain the exponential decay rate of the queue length probability in an intree network as was obtained by Chang [5], who considered the arrival process satisfying the sample path LDP. 相似文献
12.
We present a new approach to study the convergence of Newton's method in Banach spaces, which relax the conditions appearing in the usual studies. The approach is based on the bound required for the second derivative of the operator involved. An application to a nonlinear integral equation is presented. 相似文献
13.
14.
Agnieszka Kaamajska 《Mathematical Methods in the Applied Sciences》2006,29(11):1307-1325
The weak limits of sequences {f(uν)}ν∈? where uν's are vector‐valued µ‐measurable functions defined on a compact set Ω and f is (possibly) discontinuous are investigated. As shown by the author (J. Conv. Anal. (to appear)), they are described in terms of integral formulae involving parametrized measures independent of f, similarly as in the classical theorem by Young and its generalization due to DiPerna and Majda. In the present paper we describe the supports of the involved parametrized measures. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
15.
In this paper we consider an initial boundary value problem for a reaction-diffusion equation under nonlinear and nonlocal Robin type boundary condition. Assuming the existence of an ordered pair of upper and lower solutions we establish a generalized quasilinearization method for the problem under consideration whose characteristic feature consists in the construction of monotone sequences converging to the unique solution within the interval of upper and lower solutions, and whose convergence rate is quadratic. Thus this method provides an efficient iteration technique that produces not only improved approximations due to the monotonicity of its iterates, but yields also a measure of the convergence rate. 相似文献
16.
考虑约束最优化问题:minx∈Ωf(x)其中:f:R^n→R是连续可微函数,Ω是一闭凸集。本文研究了解决此问题的梯度投影方法,在步长的选取时采用了一种新的策略,在较弱的条件下,证明了梯度投影响方法的全局收敛性。 相似文献
17.
A Modified Quasi-Newton Method for Structured Optimization with Partial Information on the Hessian 总被引:2,自引:0,他引:2
This paper develops a modified quasi-Newton method for structured unconstrained optimization with partial information on the
Hessian, based on a better approximation to the Hessian in current search direction. The new approximation is decided by both
function values and gradients at the last two iterations unlike the original one which only uses the gradients at the last
two iterations. The modified method owns local and superlinear convergence. Numerical experiments show that the proposed method
is encouraging comparing with the methods proposed in [4] for structured unconstrained optimization
Presented at the 6th International Conference on Optimization: Techniques and Applications, Ballarat, Australia, December
9–11, 2004 相似文献
18.
19.
By using the quasi-Lyapunov function, some sufficient conditions of global exponential stability for impulsive systems are established, which is the basis for the following discussion. Then, by employing Riccati inequality and Hamilton-Jacobi inequality approach, some sufficient conditions of robust exponential stability for uncertain linear/nonlinear impulsive systems are derived, respectively. Finally, some examples are given to illustrate the applications of the theory. 相似文献
20.
姜德元 《浙江大学学报(理学版)》2003,30(5):499-502
研究了NA序列重对数律收敛速度的一般形式,把Davis和Gut的结果推广到了NA的情形,并使梁汉营等人关于对数律一个结果成为特例;作为推论,得到了关于NA序列重对数律收敛速度的充分条件. 相似文献