全文获取类型
收费全文 | 77647篇 |
免费 | 557篇 |
国内免费 | 112篇 |
专业分类
化学 | 41261篇 |
晶体学 | 1260篇 |
力学 | 3277篇 |
综合类 | 1篇 |
数学 | 7829篇 |
物理学 | 24688篇 |
出版年
2022年 | 629篇 |
2021年 | 871篇 |
2020年 | 965篇 |
2019年 | 1104篇 |
2018年 | 1596篇 |
2017年 | 1686篇 |
2016年 | 2148篇 |
2015年 | 1022篇 |
2014年 | 1718篇 |
2013年 | 3269篇 |
2012年 | 2896篇 |
2011年 | 3274篇 |
2010年 | 2636篇 |
2009年 | 2634篇 |
2008年 | 2996篇 |
2007年 | 2872篇 |
2006年 | 2767篇 |
2005年 | 2432篇 |
2004年 | 2237篇 |
2003年 | 2072篇 |
2002年 | 2133篇 |
2001年 | 2233篇 |
2000年 | 1624篇 |
1999年 | 1252篇 |
1998年 | 1125篇 |
1997年 | 1036篇 |
1996年 | 891篇 |
1995年 | 831篇 |
1994年 | 811篇 |
1993年 | 811篇 |
1992年 | 864篇 |
1991年 | 933篇 |
1990年 | 877篇 |
1989年 | 905篇 |
1988年 | 816篇 |
1987年 | 767篇 |
1986年 | 739篇 |
1985年 | 864篇 |
1984年 | 961篇 |
1983年 | 818篇 |
1982年 | 834篇 |
1981年 | 746篇 |
1980年 | 701篇 |
1979年 | 768篇 |
1978年 | 890篇 |
1977年 | 913篇 |
1976年 | 808篇 |
1975年 | 774篇 |
1974年 | 790篇 |
1973年 | 760篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
A. Hagfeldt S. Lunell H. O. G. Sieghbahn 《International journal of quantum chemistry》1994,49(2):97-104
The energy levels of small titanium oxide clusters [(TiO2)2, and (TiO2H)3, and (TiO2H)2] have been calculated using ab initio SCF methods. Both crystal and relaxed geometries have been considered. Systematic changes in the valencelevel structure resulting from geometry relaxation are found, which may be related to band-gap changes experimentally observed for small titanium oxide particles. In addition, a Ti? OH local surface state is found to be well described within a limited cluster model. © 1994 John Wiley & Sons, Inc. 相似文献
52.
53.
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
54.
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
55.
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
56.
57.
58.
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
59.
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
60.
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