全文获取类型
收费全文 | 8868篇 |
免费 | 784篇 |
国内免费 | 901篇 |
专业分类
化学 | 704篇 |
晶体学 | 27篇 |
力学 | 518篇 |
综合类 | 231篇 |
数学 | 8186篇 |
物理学 | 887篇 |
出版年
2024年 | 12篇 |
2023年 | 66篇 |
2022年 | 130篇 |
2021年 | 167篇 |
2020年 | 165篇 |
2019年 | 212篇 |
2018年 | 183篇 |
2017年 | 277篇 |
2016年 | 309篇 |
2015年 | 181篇 |
2014年 | 407篇 |
2013年 | 684篇 |
2012年 | 428篇 |
2011年 | 516篇 |
2010年 | 482篇 |
2009年 | 560篇 |
2008年 | 627篇 |
2007年 | 652篇 |
2006年 | 549篇 |
2005年 | 482篇 |
2004年 | 428篇 |
2003年 | 396篇 |
2002年 | 362篇 |
2001年 | 314篇 |
2000年 | 293篇 |
1999年 | 235篇 |
1998年 | 229篇 |
1997年 | 216篇 |
1996年 | 177篇 |
1995年 | 111篇 |
1994年 | 103篇 |
1993年 | 64篇 |
1992年 | 57篇 |
1991年 | 65篇 |
1990年 | 49篇 |
1989年 | 28篇 |
1988年 | 29篇 |
1987年 | 29篇 |
1986年 | 17篇 |
1985年 | 38篇 |
1984年 | 30篇 |
1983年 | 37篇 |
1982年 | 36篇 |
1981年 | 32篇 |
1980年 | 32篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 6篇 |
1972年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
§ 1 IntroductionRecently,certain three-point boundary value problems for nonlinear ordinarydifferential equations have been studied by many authors[1— 6] .However,few papers havebeen published on the same problems for nonlinear functional differential equations.In thispaper,we are concerned with the following second order differential equation with anadvanced argumentu″(t) +λa(t) f(u(h(t) ) ) =0 ,t∈ (0 ,1 ) (1 .1 )with the three-point boundary conditionsu(0 ) =0 ,αu(η) =u(1 ) ,(1 .2 )… 相似文献
72.
曾六川 《高校应用数学学报(英文版)》2003,18(3):283-286
Let(X,‖·‖ ) be a Banach space.Let K be a nonempty closed,convex subset of Xand T∶K→K.Assume that T is Lipschitzian,i.e.there exists L>0 such that‖ T(x) -T(y)‖≤ L‖ x -y‖for all x,y∈K.Withoutloss of generality,assume that L≥ 1 .Assume also that T is strictly pseudocontractive.According to[1 ] this may be statedas:there exists k∈ (0 ,1 ) such that‖ x -y‖≤‖ x -y + r[(I -T -k I) x -(I -T -k I) y]‖for all r>0 and all x,y∈ K.Throughout,let N denote the set of positive in… 相似文献
73.
曾六川 《高等学校计算数学学报(英文版)》2003,12(1)
The purpose of this paper is to investigate the problem of approximating fixed points of non-Lipschitizian asymptotically pseudocontractive mappings in an arbitrary real Banach space by the modified Ishikawa iterative sequences with errors. 相似文献
74.
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
75.
ShiHongCHENG 《数学学报(英文版)》2003,19(1):177-186
We give an Edgeworth expansion for densities of order statistics with fixed rank k.The Edgeworth expansion for densities of extreme values is then obtained as a special case k=1. 相似文献
76.
Valuable insights into the problem of how to fund defined benefitpension schemes can be obtained by analysis using the standardBlackScholes/Merton option pricing model, consideringthe pension fund finances jointly with those of the sponsoringcompany. The nature of the fund assets and liabilities is completelydifferent, and this lies behind current controversies aboutthe appropriate discount rate, valuation, financial accountingand preferential status for pension fund claimants in insolvency. 相似文献
77.
78.
Milan Práger 《Applications of Mathematics》2003,48(3):225-236
Fast direct solvers for the Poisson equation with homogeneous Dirichlet and Neumann boundary conditions on special triangles and tetrahedra are constructed. The domain given is extended by symmetrization or skew symmetrization onto a rectangle or a rectangular parallelepiped and a fast direct solver is used there. All extendable domains are found. Eigenproblems are also considered. 相似文献
79.
This paper deals with the solvability of boundary value problems for singular integral equations of the form (i)-(ii).By an algebraic method we reduce the problem (i)-(ii) to a system of linear algebraic equations which gives all solutions in a closed form.AMS Subject Classification: 47G05, 45GO5, 45E05 相似文献
80.
Alec Stephenson 《Extremes》2003,6(1):49-59
Methods are given for simulating from symmetric and asymmetric versions of the multivariate logistic distribution, and from other multivariate extreme value distributions based on the well known logistic model. We consider two general approaches. The first approach uses transformations to derive random variables with a joint distribution function from which it is easy to simulate. The second approach derives from a specification of conditionally independent marginal components, conditioning on positive stable random variables. This specification extends to models of nested or hierarchical type and leads to an efficient way of incorporating marginal censoring. The algorithms presented in Sections 2 and 3 are available on request from the author. They are also included in the R (Ihaka and Gentleman, 1996) package evd (Stephenson, 2002), which is available from http://www.maths.lancs.ac.uk/~stephena/. 相似文献