全文获取类型
收费全文 | 16448篇 |
免费 | 1290篇 |
国内免费 | 794篇 |
专业分类
化学 | 445篇 |
晶体学 | 10篇 |
力学 | 2267篇 |
综合类 | 108篇 |
数学 | 12751篇 |
物理学 | 2951篇 |
出版年
2024年 | 37篇 |
2023年 | 175篇 |
2022年 | 145篇 |
2021年 | 246篇 |
2020年 | 454篇 |
2019年 | 445篇 |
2018年 | 451篇 |
2017年 | 438篇 |
2016年 | 428篇 |
2015年 | 392篇 |
2014年 | 685篇 |
2013年 | 1784篇 |
2012年 | 633篇 |
2011年 | 951篇 |
2010年 | 763篇 |
2009年 | 1061篇 |
2008年 | 1039篇 |
2007年 | 967篇 |
2006年 | 888篇 |
2005年 | 687篇 |
2004年 | 619篇 |
2003年 | 612篇 |
2002年 | 609篇 |
2001年 | 488篇 |
2000年 | 494篇 |
1999年 | 450篇 |
1998年 | 374篇 |
1997年 | 358篇 |
1996年 | 263篇 |
1995年 | 186篇 |
1994年 | 172篇 |
1993年 | 141篇 |
1992年 | 104篇 |
1991年 | 92篇 |
1990年 | 83篇 |
1989年 | 61篇 |
1988年 | 46篇 |
1987年 | 51篇 |
1986年 | 38篇 |
1985年 | 65篇 |
1984年 | 104篇 |
1983年 | 51篇 |
1982年 | 67篇 |
1981年 | 64篇 |
1980年 | 59篇 |
1979年 | 56篇 |
1978年 | 54篇 |
1977年 | 33篇 |
1976年 | 27篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Cai Xiaochun 《Annals of Differential Equations》2006,22(1):1-6
In this paper, we apply a critical point theorem and obtain the condition for the existence of three solutions to two-point boundary value problem of a second order nonlinear difference equation. 相似文献
992.
In this paper, the existence of positive periodic solutions for infinite delay functional differential equations(FDEs for short) is discussed by utilizing a fixed point theorem on a cone in Banach space. Some results on the existence of positive periodic solutions are derived. 相似文献
993.
Dirichlet boundary value problems for perturbed second-order differential equations on a half line are investigated in this paper. The methods mainly depend on the calculus of variations to the classical functionals. Sufficient conditions are obtained for the existence of the solutions. 相似文献
994.
Zheng-su Wan Ben-yu Guo Zhong-qing Wang 《计算数学(英文版)》2006,24(4):481-500
In this paper, we investigate Jacobi pseudospectral method for fourth order problems. We establish some basic results on the Jacobi-Gauss-type interpolations in non-uniformly weighted Sobolev spaces, which serve as important tools in analysis of numerical quadratures, and numerical methods of differential and integral equations. Then we propose Jacobi pseudospectral schemes for several singular problems and multiple-dimensional problems of fourth order. Numerical results demonstrate the spectral accuracy of these schemes, and coincide well with theoretical analysis. 相似文献
995.
Convergence to Diffusion Waves for Nonlinear Evolution Equations with Ellipticity and Damping, and with Different End States 总被引:1,自引:0,他引:1
Chang Jiang ZHU Zhi Yong ZHANG Hui YIN 《数学学报(英文版)》2006,22(5):1357-1370
In this paper, we consider the global existence and the asymptotic behavior of solutions to the Cauchy problem for the following nonlinear evolution equations with ellipticity and dissipative effects: {ψt=-(1-α)ψ-θx+αψxx, θt=-(1-α)θ+νψx+(ψθ)x+αθxx(E) with initial data (ψ,θ)(x,0)=(ψ0(x),θ0(x))→(ψ±,θ±)as x→±∞ where α and ν are positive constants such that α 〈 1, ν 〈 4α(1 - α). Under the assumption that |ψ+ - ψ-| + |θ+ - θ-| is sufficiently small, we show the global existence of the solutions to Cauchy problem (E) and (I) if the initial data is a small perturbation. And the decay rates of the solutions with exponential rates also are obtained. The analysis is based on the energy method. 相似文献
996.
On the solution of the non-local parabolic partial differential equations via radial basis functions
In this paper, the problem of solving the one-dimensional parabolic partial differential equation subject to given initial and non-local boundary conditions is considered. The approximate solution is found using the radial basis functions collocation method. There are some difficulties in computing the solution of the time dependent partial differential equations using radial basis functions. If time and space are discretized using radial basis functions, the resulted coefficient matrix will be very ill-conditioned and so the corresponding linear system cannot be solved easily. As an alternative method for solution, we can use finite-difference methods for discretization of time and radial basis functions for discretization of space. Although this method is easy to use but an accurate solution cannot be provided. In this work an efficient collocation method is proposed for solving non-local parabolic partial differential equations using radial basis functions. Numerical results are presented and are compared with some existing methods. 相似文献
997.
Hideshi Yamane 《Proceedings of the American Mathematical Society》2006,134(11):3353-3361
We study the lifespan of solutions to fully nonlinear Cauchy problems with small real- or complex-analytic data. Our proofs are based on the method of majorants and the fixed point theorem for a contraction mapping.
998.
S. Boulite L. Maniar G. M. N'Gué ré kata 《Proceedings of the American Mathematical Society》2006,134(12):3613-3624
In this work, we use the extrapolation methods to study the existence and uniqueness of almost automorphic solutions to the semilinear boundary differential equation
where generates a hyperbolic -semigroup on a Banach space and are almost automorphic functions which take values in and a ``boundary space' , respectively. These equations are an abstract formulation of partial differential equations with semilinear terms at the boundary, such as population equations, retarded differential equations and boundary control systems. An application to retarded differential equations is given.
where generates a hyperbolic -semigroup on a Banach space and are almost automorphic functions which take values in and a ``boundary space' , respectively. These equations are an abstract formulation of partial differential equations with semilinear terms at the boundary, such as population equations, retarded differential equations and boundary control systems. An application to retarded differential equations is given.
999.
Gaocheng Yue Chengkui Zhong 《Nonlinear Analysis: Theory, Methods & Applications》2009,71(9):4105-4114
A plate equation with critical exponent in locally uniform spaces with a coefficient β(x) belonging to the locally uniform spaces is studied. This equation is shown to generate a dissipative semigroup in locally uniform spaces , which possesses global attractors in weighted spaces . 相似文献
1000.
M.H.M. Rashid Yahya El-Qaderi 《Nonlinear Analysis: Theory, Methods & Applications》2009,71(12):6276-6282
In this paper, we study the local and global existence of mild solutions to a class of fractional integro-differential equations in an arbitrary Banach space associated with operators generating compact semigroup on the Banach space. 相似文献