全文获取类型
收费全文 | 1828篇 |
免费 | 207篇 |
国内免费 | 140篇 |
专业分类
化学 | 22篇 |
力学 | 91篇 |
综合类 | 17篇 |
数学 | 1872篇 |
物理学 | 173篇 |
出版年
2023年 | 18篇 |
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 44篇 |
2019年 | 39篇 |
2018年 | 61篇 |
2017年 | 60篇 |
2016年 | 43篇 |
2015年 | 54篇 |
2014年 | 73篇 |
2013年 | 211篇 |
2012年 | 81篇 |
2011年 | 84篇 |
2010年 | 78篇 |
2009年 | 94篇 |
2008年 | 120篇 |
2007年 | 137篇 |
2006年 | 96篇 |
2005年 | 126篇 |
2004年 | 73篇 |
2003年 | 92篇 |
2002年 | 85篇 |
2001年 | 67篇 |
2000年 | 53篇 |
1999年 | 63篇 |
1998年 | 71篇 |
1997年 | 43篇 |
1996年 | 28篇 |
1995年 | 26篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2175条查询结果,搜索用时 15 毫秒
1.
2.
3.
Gurusamy Arumugam Jagmohan Tyagi 《Mathematical Methods in the Applied Sciences》2020,43(10):6576-6597
We establish the existence of nonnegative weak solutions to nonlinear reaction–diffusion system with cross-diffusion and nonstandard growth conditions subject to the homogeneous Neumann boundary conditions. We assume that the diffusion operators satisfy certain monotonicity condition and nonstandard growth conditions and prove that the existence of weak solutions using Galerkin's approximation technique. 相似文献
4.
Recent Progress in the $L_p$ Theory for Elliptic and Parabolic Equations with Discontinuous Coefficients 下载免费PDF全文
Hongjie Dong 《分析论及其应用》2020,36(2):161-199
In this paper, we review some results over the last 10-15 years on elliptic and parabolic equations with discontinuous coefficients. We begin with an approach given by N. V. Krylov to parabolic equations in the whole space with $\rm{VMO}_x$ coefficients. We then discuss some subsequent development including elliptic and parabolic equations with coefficients which are allowed to be merely measurable in one or two space directions, weighted $L_p$estimates with Muckenhoupt ($A_p$) weights, non-local elliptic and parabolic equations, as well as fully nonlinear elliptic and parabolic equations. 相似文献
5.
《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2020,37(5):1185-1209
We establish the existence of solutions of the Cauchy problem for a higher-order semilinear parabolic equation by introducing a new majorizing kernel. We also study necessary conditions on the initial data for the existence of local-in-time solutions and identify the strongest singularity of the initial data for the solvability of the Cauchy problem. 相似文献
6.
Giuseppe Vacca Lourenco Beirão da Veiga 《Numerical Methods for Partial Differential Equations》2015,31(6):2110-2134
The virtual element method (VEM) is a recent technology that can make use of very general polygonal/polyhedral meshes without the need to integrate complex nonpolynomial functions on the elements and preserving an optimal order of convergence. In this article, we develop for the first time, the VEM for parabolic problems on polygonal meshes, considering time‐dependent diffusion as our model problem. After presenting the scheme, we develop a theoretical analysis and show the practical behavior of the proposed method through a large array of numerical tests. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 2110–2134, 2015 相似文献
7.
ABSTRACTA class of semilinear parabolic reaction diffusion equations with multiple time delays is considered. These time delays and corresponding weights are to be optimized such that the associated solution of the delay equation is the best approximation of a desired state function. The differentiability of the mapping is proved that associates the solution of the delay equation to the vector of weights and delays. Based on an adjoint calculus, first-order necessary optimality conditions are derived. Numerical test examples show the applicability of the concept of optimizing time delays. 相似文献
8.
This paper develops a framework to deal with the unconditional superclose analysis of
nonlinear parabolic equation. Taking the finite element pair $Q_{11}/Q_{01} × Q_{10}$ as an example,
a new mixed finite element method (FEM) is established and the $τ$ -independent superclose
results of the original variable $u$ in $H^1$-norm and the flux variable $\mathop{q} \limits ^{\rightarrow}= −a(u)∇u$ in $L^2$-norm are deduced ($τ$ is the temporal partition parameter). A key to our analysis is an
error splitting technique, with which the time-discrete and the spatial-discrete systems are
constructed, respectively. For the first system, the boundedness of the temporal errors is obtained. For the second system, the spatial superclose results are presented unconditionally, while the previous literature always only obtain the convergent estimates or require
certain time step conditions. Finally, some numerical results are provided to confirm the
theoretical analysis, and show the efficiency of the proposed method. 相似文献
9.
10.