全文获取类型
收费全文 | 83443篇 |
免费 | 708篇 |
国内免费 | 157篇 |
专业分类
化学 | 44855篇 |
晶体学 | 1295篇 |
力学 | 3484篇 |
综合类 | 1篇 |
数学 | 9099篇 |
物理学 | 25574篇 |
出版年
2022年 | 618篇 |
2021年 | 926篇 |
2020年 | 1029篇 |
2019年 | 1169篇 |
2018年 | 1654篇 |
2017年 | 1731篇 |
2016年 | 2244篇 |
2015年 | 1137篇 |
2014年 | 1849篇 |
2013年 | 3577篇 |
2012年 | 3190篇 |
2011年 | 3597篇 |
2010年 | 2856篇 |
2009年 | 2839篇 |
2008年 | 3296篇 |
2007年 | 3179篇 |
2006年 | 3067篇 |
2005年 | 2702篇 |
2004年 | 2504篇 |
2003年 | 2285篇 |
2002年 | 2338篇 |
2001年 | 2331篇 |
2000年 | 1714篇 |
1999年 | 1349篇 |
1998年 | 1197篇 |
1997年 | 1098篇 |
1996年 | 981篇 |
1995年 | 896篇 |
1994年 | 884篇 |
1993年 | 892篇 |
1992年 | 928篇 |
1991年 | 976篇 |
1990年 | 951篇 |
1989年 | 964篇 |
1988年 | 863篇 |
1987年 | 820篇 |
1986年 | 786篇 |
1985年 | 931篇 |
1984年 | 1039篇 |
1983年 | 869篇 |
1982年 | 908篇 |
1981年 | 825篇 |
1980年 | 795篇 |
1979年 | 843篇 |
1978年 | 970篇 |
1977年 | 988篇 |
1976年 | 879篇 |
1975年 | 825篇 |
1974年 | 828篇 |
1973年 | 818篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
71.
The microhardness and content of carbon in electroplated gold coatings were studied as influenced by the operation time of citrate and citrate-phosphate gold-plating electrolytes. Such physicomechanical properties as porosity, microhardness, internal stress, plasticity, and microstructure of electroless-plated and electroplated nickel coatings were studied and analyzed. 相似文献
72.
We consider the inverse problem for the identification of the coefficient in a parabolic equation. The model is applied to describe the functioning of a hierarchical structure [1]; it is also relevant for heat-conduction theory [2]. Unique solvability of the inverse problem is proved. 相似文献
73.
V. O. Tarasov 《Journal of Mathematical Sciences》1991,54(3):958-967
A mixed boundary-value problem for the nonlinear Schrödinger equation and its generalization is studied by the method used for the inverse scattering problem. A connection is established between conservation laws and boundary conditions in integrable boundary-value problems for higher nonlinear Schrödinger equations. It is shown that the generalized boundary-value problem requires a joint consideration of regular and singular solutions for the nonlinear Schrödinger equation with repulsion.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 169, pp. 151–165, 1988. 相似文献
74.
75.
76.
Summary The main purpose of this paper is to introduce the concepts of η-sets, ηζ-sets,η-continuity and ηζ-continuity and to obtain
a decomposition of continuity. 相似文献
77.
Abstract
In this note, we consider a Frémond model of shape memory alloys. Let us imagine a piece of a shape memory alloy which is
fixed on one part of its boundary, and assume that forcing terms, e.g., heat sources and external stress on the remaining
part of its boundary, converge to some time-independent functions, in appropriate senses, as time goes to infinity. Under
the above assumption, we shall discuss the asymptotic stability for the dynamical system from the viewpoint of the global
attractor. More precisely, we generalize the paper [12] dealing with the one-dimensional case. First, we show the existence
of the global attractor for the limiting autonomous dynamical system; then we characterize the asymptotic stability for the
non-autonomous case by the limiting global attractor.
* Project supported by the MIUR-COFIN 2004 research program on “Mathematical Modelling and Analysis of Free Boundary Problems”. 相似文献
78.
Zarubitskii O. G. Budnik V. G. Omel'chuk A. A. Melekhin V. T. Opanasyuk V. P. Zakharchenko N. F. 《Russian Journal of Applied Chemistry》2002,75(4):558-561
Electrochemical separation of lead-silver alloys into the constituents by thin-layer electrolysis in molten electrolytes, with bismuth as metal separator, is studied. It is proposed to determine the extent of component recovery by potentiometry. 相似文献
79.
The procedure for calculating the dispersion of the refractive and absorption indices and thickness of an optical film, based on measurements of spectral dependence of the transmittance, is described. The film parameters are calculated using a solution of the approximation problem. The effect of the film model on the calculated values of the refractive and absorption indices is analyzed. 相似文献
80.