全文获取类型
收费全文 | 21696篇 |
免费 | 1174篇 |
国内免费 | 659篇 |
专业分类
化学 | 502篇 |
晶体学 | 3篇 |
力学 | 881篇 |
综合类 | 362篇 |
数学 | 10158篇 |
物理学 | 1855篇 |
无线电 | 9768篇 |
出版年
2024年 | 107篇 |
2023年 | 395篇 |
2022年 | 542篇 |
2021年 | 485篇 |
2020年 | 378篇 |
2019年 | 265篇 |
2018年 | 184篇 |
2017年 | 583篇 |
2016年 | 811篇 |
2015年 | 616篇 |
2014年 | 1483篇 |
2013年 | 1164篇 |
2012年 | 1804篇 |
2011年 | 1697篇 |
2010年 | 1368篇 |
2009年 | 1298篇 |
2008年 | 1932篇 |
2007年 | 1071篇 |
2006年 | 999篇 |
2005年 | 1166篇 |
2004年 | 796篇 |
2003年 | 686篇 |
2002年 | 577篇 |
2001年 | 546篇 |
2000年 | 422篇 |
1999年 | 338篇 |
1998年 | 279篇 |
1997年 | 254篇 |
1996年 | 209篇 |
1995年 | 220篇 |
1994年 | 171篇 |
1993年 | 122篇 |
1992年 | 129篇 |
1991年 | 129篇 |
1990年 | 121篇 |
1989年 | 98篇 |
1988年 | 17篇 |
1987年 | 18篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1975年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
Ju-liangZhang Xiang-sunZhang Yong-meiSu 《应用数学学报(英文版)》2004,20(4):557-572
In this paper, we analyze the global and local convergence properties of two predictor-corrector smoothing methods, which are based on the framework of the method in [1], for monotone linear complementarity problems (LCPs). The difference between the algorithm in [1] and our algorithms is that the neighborhood of smoothing central path in our paper is different to that in [1]. In addition, the difference between Algorithm 2.1 and the algorithm in [1] exists in the calculation of the predictor step. Comparing with the results in [1],the global and local convergence of the two methods can be obtained under very mild conditions. The global convergence of the two methods do not need the boundness of the inverse of the Jacobian. The superlinear convergence of Algorithm 2.1‘ is obtained under the assumption of nonsingularity of generalized Jacobian of Φ(x,y) at the limit point and Algorithm 2.1 obtains superlinear convergence under the assumption of strict complementarity at the solution. The efficiency of the two methods is tested by numerical experiments. 相似文献
902.
XinRongMA 《数学学报(英文版)》2004,20(1):157-162
In two centuries ago,Ming Autu discovered the famous Catalan numbers while he tried to expand the function sin(2px) as power series of sin(x) for the case p=1,2,3.Very recently,P.J.Larcombe shows that for any p,sin(2px) can always be expressed as an infinite power series of sin(x) involving precise combinations of Catalan numbers as part of all but the initial p terms and gave all expansions for the case p=4,5.The present paper presents the desired expansion for arbitrary integer p. 相似文献
903.
Cauchy Problem of Some Doubly Degenerate Parabolic Equations with Initial Datum a Measure 总被引:1,自引:0,他引:1
This paper discusses the Cauchy problem of the equation
with initial datum a measure. Under the assumption of the parameters, one proves the existence and non-existence of the non-negative
generalized solution.
Member in Partner Group of MPI for Math. in Leipzig at AMSS.
Supported by the Research Fund for Returned Overseas Chinese Scholars 20010107 相似文献
(1) |
904.
WeiJieFENG 《数学学报(英文版)》2004,20(6):983-988
In this paper, we obtain some existence results for a class of singular semilinear elliptic problems where we improve some earlier results of Zhijun Zhang. We show the existence of entire positive solutions without the monotonic condition imposed in Zhang‘s paper. The main point of our technique is to choose an approximating sequence and prove its convergence. The desired compactness can be obtained by the Sobolev embedding theorems. 相似文献
905.
提出了一个基于纠缠交换理论犤2~4犦的量子密钥分发协议。安全性分析证明此QKD协议是无条件安全,而且十分有效。 相似文献
906.
A Global Solution to a
Two-dimensional Riemann Problem Involving Shocks as Free
Boundaries 总被引:4,自引:0,他引:4
YuxiZheng 《应用数学学报(英文版)》2003,19(4):559-572
We present a global solution to a Riemann problem for the pressure gradient system of equations.The Riemann problem has initially two shock waves and two contact discontinuities. The angle between the two shock waves is set initially to be close to 180 degrees. The solution has a shock wave that is usually regarded as a free boundary in the self-similar variable plane. Our main contribution in methodology is handling the tangential oblique derivative boundary values. 相似文献
907.
On the Upper Bound of Second Eigenvalues for Uniformly Elliptic Operators of any Orders 总被引:1,自引:0,他引:1
Gao Jia Xiao-ping Yang Chun-lin QianBengbu Tank Institute Bengbu China & School of Science Nanjing University of Science Technology Nanjing ChinaSchool of Science Nanjing University of Science Technology Nanjing China Suzhou Television & Radio Broadcasting University Suzhou China 《应用数学学报(英文版)》2003,19(1):107-116
Abstract Let Ω R~m(m≥1)be a bounded domain with piecewise smooth boundary Ω.Let t and r bepositive integers with t>r+1. We consider the eigenvalue problems(1.1)and(12),and obtain Theorem 1and Theorem 2, which generalize the results in[1,2.5]. 相似文献
908.
“调配问题”的动态规划模型与计算 总被引:1,自引:0,他引:1
本给出了调配问题的动态规划模型与计算,该表征更具一般化,且便于计算机计算。 相似文献
909.
ZHOU Yi 《数学年刊B辑(英文版)》2001,22(3):275-280
gi. IntroductionThis paper deals with solutionS of certain nonlinear wave equationS Of the formcorresponding to Antial conditionSwuersis the wave OPerstor.we are interested in showing the ~ up" Of solutions to (1.1)--(1.2). For that, wereIf ac ~ 1)(n ~ 1) > 2, global solutions of ~ equation subject to very general perturbationsof order p exist Provided the initial data are swhciently small (see I6] and references therein).We are also interested in esthaattw the take when "blow up" occurs. … 相似文献
910.
将竞争机理引入网络的自动波产生与传播过程中,提出自动波竞争神经网络(ACNN)模型,并成功地应用于求解单源最短路问题,给出了基于ACNN的最短路求解算法. 与其他神经网络最短路算法相比,基于ACNN的最短路算法具有网络所需的神经元数目少、神经元及网络的结构简单、易于软硬件的实现、以及全并行方式计算等特点,可用于求解非对称赋权图的最短路径树问题,且其计算时间(迭代次数)仅正比于最短路径上的跃点数,与赋权图的复杂度、路径总长、边长的精度、通路总数等因素无关. 计算机仿真结果表明该算法的有效性和快速求解能力.
关键词:
单源最短路问题
自动波竞争神经网络
脉冲耦合神经网络 相似文献