全文获取类型
收费全文 | 7008篇 |
免费 | 87篇 |
国内免费 | 3篇 |
专业分类
化学 | 25篇 |
力学 | 39篇 |
综合类 | 1篇 |
数学 | 6691篇 |
物理学 | 342篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 61篇 |
2018年 | 80篇 |
2017年 | 37篇 |
2016年 | 27篇 |
2015年 | 35篇 |
2014年 | 99篇 |
2013年 | 331篇 |
2012年 | 167篇 |
2011年 | 354篇 |
2010年 | 391篇 |
2009年 | 521篇 |
2008年 | 517篇 |
2007年 | 463篇 |
2006年 | 247篇 |
2005年 | 174篇 |
2004年 | 100篇 |
2003年 | 125篇 |
2002年 | 149篇 |
2001年 | 169篇 |
2000年 | 188篇 |
1999年 | 197篇 |
1998年 | 245篇 |
1997年 | 202篇 |
1996年 | 137篇 |
1995年 | 136篇 |
1994年 | 159篇 |
1993年 | 148篇 |
1992年 | 171篇 |
1991年 | 153篇 |
1990年 | 159篇 |
1989年 | 167篇 |
1988年 | 110篇 |
1987年 | 96篇 |
1986年 | 120篇 |
1985年 | 94篇 |
1984年 | 113篇 |
1983年 | 41篇 |
1982年 | 90篇 |
1981年 | 53篇 |
1980年 | 89篇 |
1979年 | 62篇 |
1978年 | 68篇 |
1977年 | 24篇 |
1976年 | 7篇 |
1973年 | 3篇 |
1971年 | 2篇 |
排序方式: 共有7098条查询结果,搜索用时 46 毫秒
71.
Summary. In this paper we are interested in two phase flow problems in porous media. We use a Dual Mesh Method to discretize this
problem with finite volume schemes. In a simplified case (elliptic - hyperbolic system) we prove the convergence of approximate
solutions to the exact solutions. We use the Dual Mesh Method in physically complex problems (heterogeneous cases with non
constant total mobility). We validate numerically the Dual Mesh Method on practical examples by computing error estimates
for different test-cases.
Received March 21, 1997 / Revised version received October 13, 1997 相似文献
72.
Michael J. Puls 《Archiv der Mathematik》2007,88(6):500-506
Let p be a real number greater than one. In this paper we study the vanishing and nonvanishing of the first L
p
-cohomology space of some groups that have one end. We also make a connection between the first L
p
-cohomolgy space and the Floyd boundary of the Cayley graph of a group. We apply the result about Floyd boundaries to show
that there exists a real number p such that the first L
p
-cohomology space of a nonelementary hyperbolic group does not vanish.
Received: 4 August 2006 Revised: 2 November 2006 相似文献
73.
Summary. We examine the convergence characteristics of iterative methods based on a new preconditioning operator for solving the linear
systems arising from discretization and linearization of the steady-state Navier-Stokes equations. With a combination of analytic
and empirical results, we study the effects of fundamental parameters on convergence. We demonstrate that the preconditioned
problem has an eigenvalue distribution consisting of a tightly clustered set together with a small number of outliers. The
structure of these distributions is independent of the discretization mesh size, but the cardinality of the set of outliers
increases slowly as the viscosity becomes smaller. These characteristics are directly correlated with the convergence properties
of iterative solvers.
Received August 5, 2000 / Published online June 20, 2001 相似文献
74.
Agnès Tourin 《Numerische Mathematik》1992,62(1):75-85
Summary The reconstruction from a shaded image of a Lambertian and not self-shadowing surface illuminated by a single distant pointwise light source may be written as a first-order Hamilton-Jacobi equation.In this paper, we continue the investigation begun in E. Rouy and A. Tourin into the uniqueness of the solution of this equation; the approach is based on the viscosity solutions theory and the dynamic programming principle.More precisely, we concentrate here on the uniqueness of the viscosity solution of this equation in case the measured luminous intensity reflected by the surface is discontinuous along a smooth curve. We prove a general comparison result for a piecewise Lipschitz continuous Hamiltonian and illustrate it by numerical experiments. 相似文献
75.
Partially finite convex programming,Part I: Quasi relative interiors and duality theory 总被引:6,自引:0,他引:6
We study convex programs that involve the minimization of a convex function over a convex subset of a topological vector space, subject to a finite number of linear inequalities. We develop the notion of the quasi relative interior of a convex set, an extension of the relative interior in finite dimensions. We use this idea in a constraint qualification for a fundamental Fenchel duality result, and then deduce duality results for these problems despite the almost invariable failure of the standard Slater condition. Part II of this work studies applications to more concrete models, whose dual problems are often finite-dimensional and computationally tractable. 相似文献
76.
The general centered form for multi-variate polynomials is investigated and a computing procedure is proposed that results in a certain superset. Based on this procedure the optimal centered forms for monomials and for some special cases of polynomials are investigated. 相似文献
77.
E. N. Dancer 《Journal of Fixed Point Theory and Applications》2007,1(1):47-60
We discuss the calculation of homotopy indices on closed convex sets in a Banach space and then use these ideas to prove the
existence of multiple solutions of nonlinear elliptic equations. We obtain more information on the solutions than in earlier
work. A key idea is to calculate the homotopy index of the stable and mountain pass solutions and the connections joining
them.
Dedicated to the memory of Jean Leray 相似文献
78.
A diffusive predator-prey model in heterogeneous environment 总被引:1,自引:0,他引:1
In this paper, we demonstrate some special behavior of steady-state solutions to a predator-prey model due to the introduction of spatial heterogeneity. We show that positive steady-state solutions with certain prescribed spatial patterns can be obtained when the spatial environment is designed suitably. Moreover, we observe some essential differences of the behavior of our model from that of the classical Lotka-Volterra model that seem to arise only in the heterogeneous case. 相似文献
79.
A recent conjecture of Myerson and Sander concerns divisibility properties of certain multinomial coefficients. We obtain results in this direction by further pursuing a line of attack developed earlier by the first author. 相似文献
80.
Vieri Benci 《Advances in Mathematics》2003,173(1):50-67
The notions of “labelled set” and “numerosity” are introduced to generalize the counting process of finite sets. The resulting numbers, called numerosities, are then used to develop nonstandard analysis. The existence of a numerosity function is equivalent to the existence of a selective ultrafilter, hence it is independent of the axioms of ZFC. 相似文献