全文获取类型
收费全文 | 10689篇 |
免费 | 1860篇 |
国内免费 | 628篇 |
专业分类
化学 | 1156篇 |
晶体学 | 145篇 |
力学 | 2379篇 |
综合类 | 159篇 |
数学 | 5101篇 |
物理学 | 4237篇 |
出版年
2024年 | 19篇 |
2023年 | 94篇 |
2022年 | 156篇 |
2021年 | 186篇 |
2020年 | 272篇 |
2019年 | 230篇 |
2018年 | 212篇 |
2017年 | 325篇 |
2016年 | 366篇 |
2015年 | 247篇 |
2014年 | 455篇 |
2013年 | 724篇 |
2012年 | 526篇 |
2011年 | 517篇 |
2010年 | 492篇 |
2009年 | 551篇 |
2008年 | 609篇 |
2007年 | 712篇 |
2006年 | 644篇 |
2005年 | 661篇 |
2004年 | 557篇 |
2003年 | 614篇 |
2002年 | 528篇 |
2001年 | 455篇 |
2000年 | 433篇 |
1999年 | 404篇 |
1998年 | 314篇 |
1997年 | 298篇 |
1996年 | 201篇 |
1995年 | 182篇 |
1994年 | 137篇 |
1993年 | 151篇 |
1992年 | 112篇 |
1991年 | 95篇 |
1990年 | 84篇 |
1989年 | 47篇 |
1988年 | 57篇 |
1987年 | 53篇 |
1986年 | 45篇 |
1985年 | 62篇 |
1984年 | 52篇 |
1983年 | 27篇 |
1982年 | 35篇 |
1981年 | 46篇 |
1980年 | 26篇 |
1979年 | 34篇 |
1978年 | 42篇 |
1977年 | 32篇 |
1976年 | 20篇 |
1971年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
131.
刘春平 《数学物理学报(A辑)》2004,4(6):661-668
该文给出了一种构造非线性发展方程显式行波解的方法并用该方法得到了Hirota-Satsuma方程组,一类非线性常微分方程以及广义耦合标量场方程组的显式行波解. 相似文献
132.
M.I.Gil' 《Annals of Differential Equations》2004,20(2):145-154
The nonlocal initial problem for nonlinear nonautonomous evolution equati-ons in a Banach space is considered. It is assumed that the nonlinearities havethe local Lipschitz properties. The existence and uniqueness of mild solutionsare proved. Applications to integro-differential equations are discussed.The main tool in the paper is the normalizing mapping (the generalizednorm). 相似文献
133.
This paper studies the dynamical behavior of a class of total area dependent nonlinear age-structured forest evolution model. We give the problem of equal value for the forest system, and discuss the stable solution of system. We obtained the necessary and sufficient conditions for there exists the stable solution. 相似文献
134.
采用精密声级计和双通道声学分析仪,对林杏琴会堂的声场分布、噪声本底和混响时间作了分区测试,应用建筑声学理论对会堂的音质状况进行了分析,并提出改善会堂音质的若干建议. 相似文献
135.
This paper proposes a fully three‐dimensional non‐linear Euler methodology for solving aerodynamic and acoustic problems in the presence of strong shocks and rarefactions. It uses a discontinuous Galerkin method (DGM) within the element, and a Riemann solver (HLLC) at the boundaries to propagate rarefactions while preserving the entropy condition and capturing shocks with no spurious oscillations. This approach is thought to marry the best aspects of finite element and finite volume methods, achieving conservation while not requiring the solution of a large matrix. Examples in which shock and rarefaction waves are well captured are presented and the propagation of acoustic pulses is well demonstrated. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
136.
Under suitable assumptions, a functional central limit theorem is obtained for a three-dimensional model of Maxwellian molecules. This model is related to a nonlinear Boltzmann-type equation. It will be proved that the family of the distributions induced by fluctuation processes converges weakly. 相似文献
137.
We study elliptic systems of strongly nonlinear first-order differential equations in complex form on the plane. For such systems we develop the theory of Hilbert boundary value problems which is very much similar to the well-known theory for a holomorphic vector. Systems of nonlinear elliptic equations describe problems of interaction of several nonlinear stationary processes in the diffusive and convective mass and heat transport by hydrodynamic fluid flows. 相似文献
138.
We introduce the concept of partially strictly monotone functions and apply it to construct a class of nonlinear penalty functions for a constrained optimization problem. This class of nonlinear penalty functions includes some (nonlinear) penalty functions currently used in the literature as special cases. Assuming that the perturbation function is lower semi-continuous, we prove that the sequence of optimal values of nonlinear penalty problems converges to that of the original constrained optimization problem. First-order and second-order necessary optimality conditions of nonlinear penalty problems are derived by converting the optimality of penalty problems into that of a smooth constrained vector optimization problem. This approach allows for a concise derivation of optimality conditions of nonlinear penalty problems. Finally, we prove that each limit point of the second-order stationary points of the nonlinear penalty problems is a second-order stationary point of the original constrained optimization problem. 相似文献
139.
An analogy between social and hydrodynamic processes is developed. The relation of the state system to the passionarity theory suggested by L. N. Gumilev is discussed. 相似文献
140.