全文获取类型
收费全文 | 9029篇 |
免费 | 848篇 |
国内免费 | 597篇 |
专业分类
化学 | 3175篇 |
晶体学 | 25篇 |
力学 | 875篇 |
综合类 | 178篇 |
数学 | 3396篇 |
物理学 | 2825篇 |
出版年
2024年 | 13篇 |
2023年 | 220篇 |
2022年 | 96篇 |
2021年 | 172篇 |
2020年 | 210篇 |
2019年 | 207篇 |
2018年 | 275篇 |
2017年 | 302篇 |
2016年 | 322篇 |
2015年 | 218篇 |
2014年 | 513篇 |
2013年 | 581篇 |
2012年 | 440篇 |
2011年 | 565篇 |
2010年 | 415篇 |
2009年 | 518篇 |
2008年 | 559篇 |
2007年 | 611篇 |
2006年 | 600篇 |
2005年 | 563篇 |
2004年 | 514篇 |
2003年 | 342篇 |
2002年 | 290篇 |
2001年 | 273篇 |
2000年 | 231篇 |
1999年 | 255篇 |
1998年 | 247篇 |
1997年 | 162篇 |
1996年 | 148篇 |
1995年 | 119篇 |
1994年 | 71篇 |
1993年 | 63篇 |
1992年 | 58篇 |
1991年 | 53篇 |
1990年 | 41篇 |
1989年 | 26篇 |
1988年 | 25篇 |
1987年 | 24篇 |
1986年 | 23篇 |
1985年 | 29篇 |
1984年 | 18篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1971年 | 4篇 |
1959年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
We give some sufficient conditions for proper lower semicontinuous functions on metric spaces to have error bounds (with exponents).
For a proper convex function f on a normed space X the existence of a local error bound implies that of a global error bound. If in addition X is a Banach space, then error bounds can be characterized by the subdifferential of f. In a reflexive Banach space X, we further obtain several sufficient and necessary conditions for the existence of error bounds in terms of the lower Dini
derivative of f.
Received: April 27, 2001 / Accepted: November 6, 2001?Published online April 12, 2002 相似文献
92.
王同科 《高等学校计算数学学报(英文版)》2002,11(2):213-225
1 IntroductionFinitevolumeelementmethodorFVEMusesavolumeintegralformulationofthedif ferentialequationwithafinitepartitioningsetofvolumetodiscretizetheequation ,thenre strictstheadmissiblefunctionstoalinearfiniteelementspacetodiscretizethesolution ([1 -4 ] ) .… 相似文献
93.
In this paper, we give a convergence theorem and error estimates for an iteration method under new Kantorovitch-Ostrowski type condition using the information of higher derivatives at initial points. Compared with the corresponding study in [3],the convergence determination is established under one global condition, instead of two , on the function. 相似文献
94.
崔霞 《高等学校计算数学学报(英文版)》2002,11(1):76-88
A new alternating direction (AD) finite element (FE) scheme for 3-dimensional nonlinear parabolic equation and parabolic integro-differential equation is studied. By using AD, the 3-dimensional problem is reduced to a family of single space variable problems, calculation work is simplified; by using FE, high accuracy is kept; by using various techniques for priori estimate for differential equations such as inductive hypothesis reasoning, the difficulty arising from the nonlinearity is treated. For both FE and ADFE schemes, the convergence properties are rigorously demonstrated, the optimal H1-and L2-norm space estimates and the 0((△t)2) estimate for time variable are obtained. 相似文献
95.
奇异类内离差矩阵条件下的Fisher最优判据 总被引:1,自引:0,他引:1
特征提取是模式分类与识别的重要环节,Fisher最优判据是特征提取的基本方法之一.本文提出了一种计算奇异类内离差矩阵条件下Fisher最优判据的新方法,并给出了计算步骤. 相似文献
96.
Inexact Newton methods for the nonlinear complementarity problem 总被引:2,自引:0,他引:2
Jong-Shi Pang 《Mathematical Programming》1986,36(1):54-71
An exact Newton method for solving a nonlinear complementarity problem consists of solving a sequence of linear complementarity
subproblems. For problems of large size, solving the subproblems exactly can be very expensive. In this paper we study inexact
Newton methods for solving the nonlinear, complementarity problem. In such an inexact method, the subproblems are solved only
up to a certain degree of accuracy. The necessary accuracies that are needed to preserve the nice features of the exact Newton
method are established and analyzed. We also discuss some extensions as well as an application.
This research was based on work supported by the National Science Foundation under grant ECS-8407240. 相似文献
97.
第二类Fredholm积分方程的泰勒展开解法 总被引:3,自引:0,他引:3
本进一步发展了用Taylor公式求解第二类Fredholm积分方程的方法,并给出了近似解的误差精度分析. 相似文献
98.
Adducts of the conjugate addition of benzylamine to enantiopure amides of aroylacrylic acid possess high enantiomeric and diastereomeric purity. A high degree of stereoselectivity has been achieved by means of crystallization-induced asymmetric transformation. A practical synthesis leading to dipeptides containing homophenylalanine is depicted. 相似文献
99.
Sparse approximate inverse (SAI) techniques have recently emerged as a new class of parallel preconditioning techniques for
solving large sparse linear systems on high performance computers. The choice of the sparsity pattern of the SAI matrix is
probably the most important step in constructing an SAI preconditioner. Both dynamic and static sparsity pattern selection
approaches have been proposed by researchers. Through a few numerical experiments, we conduct a comparable study on the properties
and performance of the SAI preconditioners using the different sparsity patterns for solving some sparse linear systems.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
100.
振动系统的模态分析实验设计 总被引:8,自引:0,他引:8
利用模态分析原理和简单试验仪器,得到了直观的悬臂梁和圆盘前4阶模态振型,使学生熟悉了模态分析原理和测试方法,有利于学生对振动规律的理解. 相似文献