全文获取类型
收费全文 | 23709篇 |
免费 | 2978篇 |
国内免费 | 876篇 |
专业分类
化学 | 6521篇 |
晶体学 | 59篇 |
力学 | 2476篇 |
综合类 | 255篇 |
数学 | 10592篇 |
物理学 | 7660篇 |
出版年
2024年 | 21篇 |
2023年 | 260篇 |
2022年 | 301篇 |
2021年 | 590篇 |
2020年 | 622篇 |
2019年 | 596篇 |
2018年 | 483篇 |
2017年 | 719篇 |
2016年 | 992篇 |
2015年 | 857篇 |
2014年 | 1195篇 |
2013年 | 1833篇 |
2012年 | 1159篇 |
2011年 | 1218篇 |
2010年 | 1089篇 |
2009年 | 1416篇 |
2008年 | 1593篇 |
2007年 | 1602篇 |
2006年 | 1299篇 |
2005年 | 971篇 |
2004年 | 889篇 |
2003年 | 961篇 |
2002年 | 899篇 |
2001年 | 676篇 |
2000年 | 722篇 |
1999年 | 630篇 |
1998年 | 565篇 |
1997年 | 412篇 |
1996年 | 341篇 |
1995年 | 307篇 |
1994年 | 278篇 |
1993年 | 232篇 |
1992年 | 207篇 |
1991年 | 159篇 |
1990年 | 137篇 |
1989年 | 127篇 |
1988年 | 150篇 |
1987年 | 108篇 |
1986年 | 98篇 |
1985年 | 152篇 |
1984年 | 106篇 |
1983年 | 46篇 |
1982年 | 78篇 |
1981年 | 65篇 |
1980年 | 85篇 |
1979年 | 71篇 |
1978年 | 54篇 |
1977年 | 63篇 |
1976年 | 57篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
91.
Marko Nedeljkov 《Mathematical Methods in the Applied Sciences》2004,27(8):931-955
This work gives a condition for existence of singular and delta shock wave solutions to Riemann problem for 2×2 systems of conservation laws. For a fixed left‐hand side value of Riemann data, the condition obtained in the paper describes a set of possible right‐hand side values. The procedure is similar to the standard one of finding the Hugoniot locus. Fluxes of the considered systems are globally Lipschitz with respect to one of the dependent variables. The association in a Colombeau‐type algebra is used as a solution concept. Copyright © 2004 John Wiley &Sons, Ltd. 相似文献
92.
Mari Grobbelaar‐Van Dalsen 《Mathematical Methods in the Applied Sciences》2004,27(11):1301-1315
This paper is concerned with well‐posedness results for a mathematical model for the transversal vibrations of a two‐dimensional hybrid elastic structure consisting of a rectangular Reissner–Mindlin plate with a Timoshenko beam attached to its free edge. The model incorporates linear dynamic feedback controls along the interface between the plate and the beam. Classical semigroup methods are employed to show the unique solvability of the coupled initial‐boundary‐value problem. We also show that the energy associated with the system exhibits the property of strong stability. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
93.
Larbi Berrahmoune 《Mathematical Methods in the Applied Sciences》2004,27(12):1385-1398
We consider an initial and boundary value problem for a homogenous string subject to an internal pointwise control. The solution resulting from a non‐linear feedback is studied. We give various explicit decay estimates depending on the control position and the feedback non‐linearity. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
94.
Sergue A. Nazarov Maria Specovius‐Neugebauer 《Mathematical Methods in the Applied Sciences》2004,27(13):1507-1544
The approximation of solutions to boundary value problems on unbounded domains by those on bounded domains is one of the main applications for artificial boundary conditions. Based on asymptotic analysis, here a new method is presented to construct local artificial boundary conditions for a very general class of elliptic problems where the main asymptotic term is not known explicitly. Existence and uniqueness of approximating solutions are proved together with asymptotically precise error estimates. One class of important examples includes boundary value problems for anisotropic elasticity and piezoelectricity. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
95.
Toshihiro Kobayashi 《Mathematical Methods in the Applied Sciences》2004,27(18):2171-2184
In this paper low‐gain adaptive stabilization of undamped semilinear second‐order hyperbolic systems is considered in the case where the input and output operators are collocated. The linearized systems have an infinite number of poles and zeros on the imaginary axis. The adaptive stabilizer is constructed by a low‐gain adaptive velocity feedback. The closed‐loop system is governed by a non‐linear evolution equation. First, the well‐posedness of the closed‐loop system is shown. Next, an energy‐like function and a multiplier function are introduced and the exponential stability of the closed‐loop system is analysed. Some examples are given to illustrate the theory. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
96.
The paper discusses the relationship between weights and control vertices of two rational NURBS curves of degree two or three with all weights larger than zero when they represent the same curve parametrically and geometrically, and gives sufficient and necessary conditions for coincidence of two rational NURBS curves in non-degeneracy case. 相似文献
97.
98.
99.
汪更生 《数学物理学报(B辑英文版)》2005,25(1):7-22
This paper deals with maximum principle for some optimal control problem governed by some elliptic variational inequalities. Some state constraints are discussed. The basic techniques used here are based on those in [1] and a new penalty functional defined in this paper. 相似文献
100.
Zhu Yongliang; Pagilla Prabhakar R. 《IMA Journal of Mathematical Control and Information》2005,22(2):181-186
We derive some useful and easily computable necessary conditionsfor the existence of a positive semi-definite solution to thealgebraic Ricatti equation (ARE). A motivating example is givento highlight the usefulness of the conditions for controllerand observer designs for nonlinear systems. Further, an upperbound on the trace of the solution to the ARE is also derived. 相似文献