全文获取类型
收费全文 | 16544篇 |
免费 | 1349篇 |
国内免费 | 803篇 |
专业分类
化学 | 311篇 |
晶体学 | 8篇 |
力学 | 2242篇 |
综合类 | 112篇 |
数学 | 13102篇 |
物理学 | 2921篇 |
出版年
2024年 | 34篇 |
2023年 | 179篇 |
2022年 | 134篇 |
2021年 | 254篇 |
2020年 | 455篇 |
2019年 | 451篇 |
2018年 | 460篇 |
2017年 | 441篇 |
2016年 | 426篇 |
2015年 | 389篇 |
2014年 | 691篇 |
2013年 | 1802篇 |
2012年 | 645篇 |
2011年 | 959篇 |
2010年 | 782篇 |
2009年 | 1077篇 |
2008年 | 1046篇 |
2007年 | 970篇 |
2006年 | 896篇 |
2005年 | 682篇 |
2004年 | 622篇 |
2003年 | 622篇 |
2002年 | 625篇 |
2001年 | 494篇 |
2000年 | 502篇 |
1999年 | 450篇 |
1998年 | 377篇 |
1997年 | 361篇 |
1996年 | 269篇 |
1995年 | 183篇 |
1994年 | 171篇 |
1993年 | 144篇 |
1992年 | 105篇 |
1991年 | 94篇 |
1990年 | 84篇 |
1989年 | 60篇 |
1988年 | 46篇 |
1987年 | 50篇 |
1986年 | 40篇 |
1985年 | 65篇 |
1984年 | 102篇 |
1983年 | 52篇 |
1982年 | 65篇 |
1981年 | 65篇 |
1980年 | 58篇 |
1979年 | 56篇 |
1978年 | 55篇 |
1977年 | 34篇 |
1976年 | 30篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
111.
L. Erbe A. Peterson S.H. Saker 《Journal of Mathematical Analysis and Applications》2007,329(1):112-131
In this paper, we extend the oscillation criteria that have been established by Hille [E. Hille, Non-oscillation theorems, Trans. Amer. Math. Soc. 64 (1948) 234-252] and Nehari [Z. Nehari, Oscillation criteria for second-order linear differential equations, Trans. Amer. Math. Soc. 85 (1957) 428-445] for second-order differential equations to third-order dynamic equations on an arbitrary time scale T, which is unbounded above. Our results are essentially new even for third-order differential and difference equations, i.e., when T=R and T=N. We consider several examples to illustrate our results. 相似文献
112.
Durand William A.Pham Ngoc Dinh 《Journal of Mathematical Analysis and Applications》2003,282(1):95-106
An electromagnetic diffraction problem in a wedge shaped region is reduced to a system of coupled functional difference equations by means of Sommerfeld integrals and Malyuzhinets theorem. By introducing an integral operator it is shown that the solutions of this system of functional equations can be defined in terms of integral representations whose kernels are solutions of a singular integral equation of Cauchy-Carleman type for which an explicit solution is given. 相似文献
113.
Asymptotic methods for contact problems are expounded. Some typical integral equations are considered 相似文献
114.
A formulation of an implicit characteristic-flux-averaging method for the unsteady Euler equations with real gas effects is presented. Incorporation of a real gas into a general equation of state is achieved by considering the pressure as a function of density and specific internal energy. The Ricmann solver as well as the flux-split algorithm are modified by introducing the pressure derivatives with respect to density and internal energy. Expressions for calculating the values of the flow variables for a real gas at the cell faces are derived. The Jacobian matrices and the eigenvectors are defined for a general equation of state. The solution of the system of equations is obtained by using a mesh-sequencing method for acceleration of the convergence. Finally, a test case for a simple form of equation of state displays the differences from the corresponding solution for an ideal gas. 相似文献
115.
GLOBAL EXISTENCE FOR A CLASS OF SYSTEMSOF NONLINEAR WAVE EQUATIONS INTHREE SPACE DIMENSIONS
下载免费PDF全文
![点击此处可从《数学年刊B辑(英文版)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S. KATAYAMA 《数学年刊B辑(英文版)》2004,25(4):463-482
Consider a system of nonlinear wave equationsfor i = 1, … , m, where F, (i = 1, … , m) are smooth functions of degree 2 near the origin of their arguments, and u = (u1, … ,um), while u and x u represent the first and second derivatives of u, respectively. In this paper, the author presents a new class of nonlineaxity for which the global existence of small solutions is ensured. For example, global existence of small solutions for arbitrary cubic terms,arbitrary cubic termswill be established, provided that c12 ≠ c22. 相似文献
116.
吴臻 《数学物理学报(B辑英文版)》2004,24(1):91-99
The existence and uniqueness results of fully coupled forward-backward stochastic differential equations with stopping time (unbounded) is obtained. One kind of comparison theorem for this kind of equations is also proved. 相似文献
117.
Discrete global descent method for discrete global optimization and nonlinear integer programming 总被引:2,自引:0,他引:2
A novel method, entitled the discrete global descent method, is developed in this paper to solve discrete global optimization
problems and nonlinear integer programming problems. This method moves from one discrete minimizer of the objective function
f to another better one at each iteration with the help of an auxiliary function, entitled the discrete global descent function.
The discrete global descent function guarantees that its discrete minimizers coincide with the better discrete minimizers
of f under some standard assumptions. This property also ensures that a better discrete minimizer of f can be found by some classical local search methods. Numerical experiments on several test problems with up to 100 integer
variables and up to 1.38 × 10104 feasible points have demonstrated the applicability and efficiency of the proposed method. 相似文献
118.
Jiqin Deng 《Journal of Mathematical Analysis and Applications》2007,332(1):475-486
In this paper, by using the fixed point theory, under quite general conditions on the nonlinear term, we obtain an existence result of bounded positive solutions of Schrödinger equations in two-dimensional exterior domains. 相似文献
119.
N. E. Tovmasyan H. A. Babayan 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2007,42(4):198-204
The paper establishes some solvability conditions of the Cauchy problem for linear differential equation in the class of monotone increasing functions. The results are applied for clarifying the possibility of flight along a given trajectory under existence of braking forces. 相似文献
120.
Piotr Biler 《Reports on Mathematical Physics》2003,52(2):205-225
We study asymptotic properties of solutions to an extension to arbitrary dimensions of the astrophysical model proposed by Chavanis et al. to explain phenomena of gravitational collapse in clouds of self-gravitating particles. In particular, we show that in the two-dimensional case the solutions can be continued to global ones, while in three space dimensions large data of negative energy blow up in a finite time. Relations between isothermal, Streater's energy-transport and the present models are also studied. 相似文献