全文获取类型
收费全文 | 2023篇 |
免费 | 161篇 |
国内免费 | 175篇 |
专业分类
化学 | 11篇 |
力学 | 61篇 |
综合类 | 22篇 |
数学 | 2194篇 |
物理学 | 71篇 |
出版年
2024年 | 6篇 |
2023年 | 37篇 |
2022年 | 21篇 |
2021年 | 34篇 |
2020年 | 71篇 |
2019年 | 70篇 |
2018年 | 64篇 |
2017年 | 70篇 |
2016年 | 60篇 |
2015年 | 63篇 |
2014年 | 96篇 |
2013年 | 255篇 |
2012年 | 65篇 |
2011年 | 102篇 |
2010年 | 88篇 |
2009年 | 144篇 |
2008年 | 147篇 |
2007年 | 114篇 |
2006年 | 111篇 |
2005年 | 97篇 |
2004年 | 55篇 |
2003年 | 87篇 |
2002年 | 86篇 |
2001年 | 61篇 |
2000年 | 53篇 |
1999年 | 48篇 |
1998年 | 56篇 |
1997年 | 42篇 |
1996年 | 25篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 16篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 11篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1974年 | 1篇 |
1973年 | 4篇 |
排序方式: 共有2359条查询结果,搜索用时 15 毫秒
41.
This paper is concerned with a one-dimensional nonisentropic compressible planar magnetohydrodynamic flow with general initial data, whose behaviors at far fields x→±∞ are different. The low Mach limit for the system is rigorously justified. The limit relies on the uniform estimates including weighted time derivatives and an extended convergence lemma. 相似文献
42.
Jules K. Djoko Virginie S. Konlack Mohamed Mbehou 《Numerical Methods for Partial Differential Equations》2020,36(1):86-117
In this work, we consider the heat equation coupled with Stokes equations under threshold type boundary condition. The conditions for existence and uniqueness of the weak solution are made clear. Next we formulate the finite element problem, recall the conditions of its solvability, and study its convergence by making use of Babuska–Brezzi's conditions for mixed problems. Third we formulate an Uzawa's type iterative algorithm that separates the fluid from heat conduction, study its feasibility, and convergence. Finally the theoretical findings are validated by numerical simulations. 相似文献
43.
Weiliang Xiao & Xuhuan Zhou 《数学研究》2020,53(3):316-328
We study a kind of generalized porous medium equation with fractional Laplacian and abstract pressure term. For a large class of equations corresponding to the form: $u_t+nu Lambda^{beta}u=nablacdot(unabla Pu)$, we get their local well-posedness in Fourier-Besov spaces for large initial data. If the initial data is small, then the solution becomes global. Furthermore, we prove a blowup criterion for the solutions. 相似文献
44.
Ieva
Dauickait Amos S. Lawless Jennifer A. Scott Peter Jan van Leeuwen 《Numerical Linear Algebra with Applications》2020,27(5)
We consider the large sparse symmetric linear systems of equations that arise in the solution of weak constraint four‐dimensional variational data assimilation, a method of high interest for numerical weather prediction. These systems can be written as saddle point systems with a 3 × 3 block structure but block eliminations can be performed to reduce them to saddle point systems with a 2 × 2 block structure, or further to symmetric positive definite systems. In this article, we analyse how sensitive the spectra of these matrices are to the number of observations of the underlying dynamical system. We also obtain bounds on the eigenvalues of the matrices. Numerical experiments are used to confirm the theoretical analysis and bounds. 相似文献
45.
Michael Goldberg 《Proceedings of the American Mathematical Society》2007,135(10):3171-3179
We prove a dispersive estimate for the Schrödinger equation on the real line, mapping between weighted spaces with stronger time-decay ( versus ) than is possible on unweighted spaces. To satisfy this bound, the long-term behavior of solutions must include transport away from the origin. Our primary requirements are that be integrable and not have a resonance at zero energy. If a resonance is present (for example, in the free case), similar estimates are valid after projecting away from a rank-one subspace corresponding to the resonance.
46.
A. V. Martynenko A. F. Tedeev 《Computational Mathematics and Mathematical Physics》2007,47(2):238-248
The following quasilinear parabolic equation with a source term and an inhomogeneous density is considered: . The conditions on the parameters of the problem are found under which the solution to the Cauchy problem blows up in a finite time. A sharp universal (i.e., independent of the initial function) estimate of the solution near the blowup time is obtained.
相似文献
$\rho (x)\frac{{\partial u}}{{\partial t}} = div(u^{m - 1} \left| {Du} \right|^{\lambda - 1} Du) + u^p $
47.
V. A. Abilov G. A. Dzhalaeva M. K. Kerimov 《Computational Mathematics and Mathematical Physics》2007,47(8):1243-1252
Some problems of expansion of functions of two variables in mixed Fourier-Jacobi series are discussed. In particular, estimates of the convergence rate of these series on classes of functions of two variables characterized by generalized moduli of continuity are given. Applications of these results and estimation of residues of some Chebyshev-type mixed cubature formulas are discussed. 相似文献
48.
For matrices whose eigenvalues are real (such as Hermitian or real symmetric matrices), we derive simple explicit estimates for the maximal (λmax) and the minimal (λmin) eigenvalues in terms of determinants of order less than 3. For 3 × 3 matrices, we derive sharper estimates, which use det A but do not require to solve cubic equations. 相似文献
49.
美式期权定价中非局部问题的有限元方法 总被引:1,自引:1,他引:1
在本文中 ,我们关心的是美式期权的有限元方法 .首先 ,根据 [4 ]我们对所讨论的问题引进一个新奇的实用的方法 ,它涉及到对原问题重新形成准确的数学公式 ,使得数值解的计算可以在非常小的区域上进行 ,从而该算法计算速度快精度高 .进而 ,我们利用超逼近分析技术得到了有限元解关于 L2 -模的最优估计 . 相似文献
50.
We study the existence and the continuity properties of the boundary values on the real axis of the resolvent of a self-adjoint operator H in the framework of the conjugate operator method initiated by Mourre. We allow the conjugate operator A to be the generator of a C0-semigroup (finer estimates require A to be maximal symmetric) and we consider situations where the first commutator [H,iA] is not comparable to H. The applications include the spectral theory of zero mass quantum field models. 相似文献