全文获取类型
收费全文 | 10115篇 |
免费 | 1108篇 |
国内免费 | 797篇 |
专业分类
化学 | 716篇 |
晶体学 | 6篇 |
力学 | 952篇 |
综合类 | 184篇 |
数学 | 6921篇 |
物理学 | 3241篇 |
出版年
2024年 | 7篇 |
2023年 | 99篇 |
2022年 | 136篇 |
2021年 | 152篇 |
2020年 | 219篇 |
2019年 | 199篇 |
2018年 | 207篇 |
2017年 | 292篇 |
2016年 | 345篇 |
2015年 | 243篇 |
2014年 | 471篇 |
2013年 | 781篇 |
2012年 | 551篇 |
2011年 | 580篇 |
2010年 | 470篇 |
2009年 | 622篇 |
2008年 | 673篇 |
2007年 | 671篇 |
2006年 | 650篇 |
2005年 | 540篇 |
2004年 | 456篇 |
2003年 | 464篇 |
2002年 | 426篇 |
2001年 | 393篇 |
2000年 | 345篇 |
1999年 | 334篇 |
1998年 | 278篇 |
1997年 | 211篇 |
1996年 | 218篇 |
1995年 | 144篇 |
1994年 | 105篇 |
1993年 | 95篇 |
1992年 | 77篇 |
1991年 | 59篇 |
1990年 | 62篇 |
1989年 | 32篇 |
1988年 | 52篇 |
1987年 | 40篇 |
1986年 | 32篇 |
1985年 | 52篇 |
1984年 | 45篇 |
1983年 | 20篇 |
1982年 | 31篇 |
1981年 | 19篇 |
1980年 | 23篇 |
1979年 | 30篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 11篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Spectral and Pseudospectral Approximations Using Hermite Functions: Application to the Dirac Equation 总被引:1,自引:0,他引:1
We consider in this paper spectral and pseudospectral approximations using Hermite functions for PDEs on the whole line. We first develop some basic approximation results associated with the projections and interpolations in the spaces spanned by Hermite functions. These results play important roles in the analysis of the related spectral and pseudospectral methods. We then consider, as an example of applications, spectral and pseudospectral approximations of the Dirac equation using Hermite functions. In particular, these schemes preserve the essential conservation property of the Dirac equation. We also present some numerical results which illustrate the effectiveness of these methods. 相似文献
62.
加速牛顿迭代收敛的新方法 总被引:2,自引:0,他引:2
提出了加速牛顿迭代收敛的新思想,构造出一类加权牛顿迭代格式,通过选取最优加权因子,使得该格式具有高阶收敛性和较小的渐近误差常数。 相似文献
63.
杨青 《高等学校计算数学学报(英文版)》2003,12(2)
The mathematical model of semiconductor devices is described by the initial boundary value problem of a system of three nonlinear partial differential equations. One equation in elliptic form is for the electrostatic potential; two equations of convection-dominated diffusion type are for the electron and hole concentrations. Finite volume element procedure are put forward for the electrostatic potential, while upwind 相似文献
64.
65.
D. Barrios Rolanía G. Lpez Lagomasino E. B. Saff 《Journal of Approximation Theory》2003,124(2):263-281
Using a convergence theorem for Fourier–Padé approximants constructed from orthogonal polynomials on the unit circle, we prove an analogue of Hadamard's theorem for determining the radius of m-meromorphy of a function analytic on the unit disk and apply this to the location of poles of the reciprocal of Szeg
functions. 相似文献
66.
M.K. Gupta Vijay Gupta Manoj Kumar 《Journal of Mathematical Analysis and Applications》2007,330(2):799-816
In the present paper we introduce a new family of linear positive operators and study some direct and inverse results in simultaneous approximation. 相似文献
67.
Somyot Plubtieng Rattanaporn Punpaeng 《Journal of Mathematical Analysis and Applications》2007,336(1):455-469
In this paper, we introduce two iterative schemes by the general iterative method for finding a common element of the set of an equilibrium problem and the set of fixed points of a nonexpansive mapping in a Hilbert space. Then, we prove two strong convergence theorems for nonexpansive mappings to solve a unique solution of the variational inequality which is the optimality condition for the minimization problem. These results extended and improved the corresponding results of Marino and Xu [G. Marino, H.K. Xu, A general iterative method for nonexpansive mapping in Hilbert spaces, J. Math. Anal. Appl. 318 (2006) 43-52], S. Takahashi and W. Takahashi [S. Takahashi, W. Takahashi, Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces, J. Math. Anal. Appl. 331 (1) (2007) 506-515], and many others. 相似文献
68.
69.
Jonathan M. Borwein 《Optimization Letters》2007,1(1):21-32
This paper is a companion to a lecture given at the Prague Spring School in Analysis in April 2006. It highlights four distinct variational methods of proving that a finite dimensional Chebyshev set is convex and hopes to inspire renewed work on the open question of whether every Chebyshev set in Hilbert space is convex. 相似文献
70.
Zhiyue Zhang Dingwen Deng 《Numerical Methods for Partial Differential Equations》2007,23(6):1530-1559
A modified backward difference time discretization is presented for Galerkin approximations for nonlinear hyperbolic equation in two space variables. This procedure uses a local approximation of the coefficients based on patches of finite elements with these procedures, a multidimensional problem can be solved as a series of one‐dimensional problems. Optimal order H01 and L2 error estimates are derived. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007 相似文献