全文获取类型
收费全文 | 4145篇 |
免费 | 382篇 |
国内免费 | 281篇 |
专业分类
化学 | 1991篇 |
晶体学 | 12篇 |
力学 | 337篇 |
综合类 | 35篇 |
数学 | 967篇 |
物理学 | 1466篇 |
出版年
2023年 | 42篇 |
2022年 | 54篇 |
2021年 | 58篇 |
2020年 | 108篇 |
2019年 | 88篇 |
2018年 | 101篇 |
2017年 | 108篇 |
2016年 | 120篇 |
2015年 | 108篇 |
2014年 | 146篇 |
2013年 | 183篇 |
2012年 | 179篇 |
2011年 | 212篇 |
2010年 | 187篇 |
2009年 | 194篇 |
2008年 | 195篇 |
2007年 | 234篇 |
2006年 | 209篇 |
2005年 | 232篇 |
2004年 | 230篇 |
2003年 | 182篇 |
2002年 | 191篇 |
2001年 | 142篇 |
2000年 | 170篇 |
1999年 | 136篇 |
1998年 | 131篇 |
1997年 | 102篇 |
1996年 | 97篇 |
1995年 | 84篇 |
1994年 | 80篇 |
1993年 | 48篇 |
1992年 | 54篇 |
1991年 | 60篇 |
1990年 | 40篇 |
1989年 | 26篇 |
1988年 | 34篇 |
1987年 | 28篇 |
1986年 | 21篇 |
1985年 | 36篇 |
1984年 | 30篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 25篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 4篇 |
1977年 | 9篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有4808条查询结果,搜索用时 15 毫秒
1.
固体间界面的物理模型和界面对声波的反射 总被引:4,自引:0,他引:4
简要描述了模拟两固体间界面特性的弹簧模型,该模型最早是根据静力学方法提出的,后来用固体间界面薄层的声波反射方法加以改进,从界面弹簧模型可以方便地得到界面外近似边界条件,其中包含界面“弹簧”振子的劲度常数和质量,文章还给出了两相间固体中界面声反射系数的表达式,介绍了测量界面劲度常数的超声反射谱方法。最后讨论了仍关声波与界面相互作用研究领域中最近的一些研究进展。 相似文献
2.
Bruno Lengeler 《Mikrochimica acta》1987,91(1-6):455-475
The synchrotron radiation (SR) emitted by circulating high-energy electrons has extraordinary properties: The light is intensive and bright, it is tunable and highly collimated, and finally, it is linearly polarized. These exceptional properties have initiated a unique revival of many spectroscopies using electromagnetic radiation. The techniques of special concern for materials analysis which are treated in this article are: X-ray absorption, reflection, fluorescence, diffraction and topography. A number of examples will be given in order to illustrate the possibilities of these techniques when SR is used.On leave of absence from Institut für Festkörperforschung, KFA Jülich, D-5170 Jülich, Federal Republic of Germany 相似文献
3.
4.
The present paper devotes to the long-time behavior of a class of reaction diffusion equations with delays under Dirichlet boundary conditions. The stability and global attractability for the zero solution are provided, and the existence, stability and attractability for the positive stationary solution are also obtained. 相似文献
5.
Koumei Tanaka 《Mathematical Methods in the Applied Sciences》2006,29(12):1451-1466
We consider a compressible viscous fluid with the velocity at infinity equal to a strictly non‐zero constant vector in ?3. Under the assumptions on the smallness of the external force and velocity at infinity, Novotny–Padula (Math. Ann. 1997; 308 :439– 489) proved the existence and uniqueness of steady flow in the class of functions possessing some pointwise decay. In this paper, we study stability of the steady flow with respect to the initial disturbance. We proved that if H3‐norm of the initial disturbance is small enough, then the solution to the non‐stationary problem exists uniquely and globally in time, which satisfies a uniform estimate on prescribed velocity at infinity and converges to the steady flow in Lq‐norm for any number q? 2. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
6.
Zhao Hanzhong 《Acta Mechanica Solida Sinica》2002,15(2):156-162
A finite difference/boundary integral procedure to determine the acoustic reflected pressure from a fluid-loaded bi-laminated
plate is described. The bi-laminate is composed of a piezoelectric layer and an elastic layer in contact with the fluid, and
is held by an acoustically hard baffle. In the numerical model, the fluid pressure at fluid/solid interface is replaced by
a continuum of point sources weighted by the normal acceleration of the elastic plate, and the governing equation system is
solved in the solid domain. With the normal acceleration found, the reflected pressure in the fluid is determined by an integral
expression involving the Green's function. It is demonstrated that an appropriate applied voltage potential across the piezoelectric
layer has the effect of cancelling either the reflected or scattered pressure of the plate at any chosen field points in the
fluid.
Project supported by the National Natural Science Foundation of China (No. 10172039). 相似文献
7.
8.
9.
Kurt Majewski 《Queueing Systems》2005,50(2-3):199-230
We consider multiclass feedforward queueing networks under first in first out and priority service disciplines driven by long-range dependent arrival and service time processes. We show that in critical loading the normalized workload, queue length and sojourn time processes can converge to a multi-dimensional reflected fractional Brownian motion. This weak heavy traffic approximation is deduced from a deterministic pathwise approximation of the network behavior close to constant critical load in terms of the solution of a Skorokhod problem. Since we model the doubly infinite time interval, our results directly cover the stationary case.AMS subject classification: primary 90B15, secondary 60K25, 68M20 相似文献
10.