全文获取类型
收费全文 | 23793篇 |
免费 | 875篇 |
国内免费 | 444篇 |
专业分类
化学 | 6089篇 |
晶体学 | 338篇 |
力学 | 640篇 |
综合类 | 55篇 |
数学 | 9514篇 |
物理学 | 8476篇 |
出版年
2023年 | 99篇 |
2022年 | 179篇 |
2021年 | 130篇 |
2020年 | 173篇 |
2019年 | 498篇 |
2018年 | 313篇 |
2017年 | 312篇 |
2016年 | 218篇 |
2015年 | 179篇 |
2014年 | 244篇 |
2013年 | 1044篇 |
2012年 | 507篇 |
2011年 | 1017篇 |
2010年 | 552篇 |
2009年 | 881篇 |
2008年 | 1009篇 |
2007年 | 996篇 |
2006年 | 948篇 |
2005年 | 639篇 |
2004年 | 1029篇 |
2003年 | 1173篇 |
2002年 | 1769篇 |
2001年 | 1788篇 |
2000年 | 1647篇 |
1999年 | 1793篇 |
1998年 | 1541篇 |
1997年 | 913篇 |
1996年 | 460篇 |
1995年 | 234篇 |
1994年 | 206篇 |
1993年 | 94篇 |
1992年 | 91篇 |
1991年 | 75篇 |
1990年 | 162篇 |
1989年 | 147篇 |
1988年 | 95篇 |
1987年 | 82篇 |
1986年 | 125篇 |
1985年 | 188篇 |
1984年 | 176篇 |
1983年 | 78篇 |
1982年 | 137篇 |
1981年 | 238篇 |
1980年 | 229篇 |
1979年 | 106篇 |
1978年 | 168篇 |
1977年 | 104篇 |
1976年 | 71篇 |
1975年 | 80篇 |
1974年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
F. Ivashchyshyn I. GrygorchakP. Stakhira V. CherpakM. Micov 《Current Applied Physics》2012,12(1):160-165
Impedance spectroscopy studies performed for intercalated multilayer structures of the type of a layered inorganic semiconductor (InSe)/conducting polymer (PEDOT:PSS) revealed low-frequency inductive response and the growth of dielectric permeability in megahertz region together with the decrease of dielectric loss angle down to one as a consequence of the conducting polymer intercalation into semiconducting layers. A model describing the unusual current-voltage characteristic is proposed. 相似文献
992.
Existence of positive solutions of singular boundary value problems related to Emden-Fowler equation is proved. A general minimization theorem in Sobolev spaces is applied. 相似文献
993.
《偏微分方程通讯》2013,38(11-12):2513-2525
ABSTRACT The Hopf map from minimal surfaces in H 3 to holomorphic quadratic differentials on H 2 is considered. Whether or not a given quadratic differential is in the image of this map is determined by the global existence/non-existence of solutions to a certain quasi-linear PDE. It is shown that this map is not surjective. 相似文献
994.
995.
In this research, we study linear difference equations with constant coefficients subject to boundary conditions. Necessary and/or sufficient conditions for the existence of a unique solution will be established. The proofs of the existence and uniqueness theorems are established by means of special types of determinants called Mosaic Vandermonde determinants. 相似文献
996.
P. P. Onys'ko T. V. Kim E. I. Kiseleva A. D. Sinytsa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):73-76
Abstract Allylic and heteroallylic compounds are classical objects of organic chemistry and can serve as models in the investigation of various theoretical problems. The anions and 1,3-dipoles generated from azaallylic derivatives are widely used in the synthesis of cyclic and acyclic nitrogen-containing compounds. 相似文献
997.
K. S. Bruzik G. M. Salamończyk B. Soboń 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):39-42
Abstract The structure and the dynamics of D-erythrostearoyl sphingomyelin has been studied by the variable temperature wide-line 31P and high-resolution 1C CP MAS NMR apectroscopy. The results indicate the formation of the highly ordered, relaxed gelphase, and are interpreted based on the conformation of D-erytgrosphingomylin in the unaggregated state. 相似文献
998.
999.
《复变函数与椭圆型方程》2012,57(15):1163-1164
Let X be a smooth and connected Riemann surface of genus g 0 and f: X P1, h: X P1 non-constant meromorphic functions on X. Fix an integer n 4 and assume the existence of n distinct points a1, , an P1 such that [image omitted] (set-theoretically) for every i. Here we prove that either f = h or [image omitted]. 相似文献
1000.
《复变函数与椭圆型方程》2012,57(7):625-626
The author offers some corrections to his article which appeared in Vol. 47, No. 3 of this journal. 相似文献