全文获取类型
收费全文 | 7420篇 |
免费 | 760篇 |
国内免费 | 722篇 |
专业分类
化学 | 1736篇 |
晶体学 | 24篇 |
力学 | 518篇 |
综合类 | 81篇 |
数学 | 5412篇 |
物理学 | 1131篇 |
出版年
2024年 | 11篇 |
2023年 | 73篇 |
2022年 | 110篇 |
2021年 | 131篇 |
2020年 | 200篇 |
2019年 | 208篇 |
2018年 | 205篇 |
2017年 | 221篇 |
2016年 | 193篇 |
2015年 | 170篇 |
2014年 | 268篇 |
2013年 | 888篇 |
2012年 | 256篇 |
2011年 | 319篇 |
2010年 | 307篇 |
2009年 | 410篇 |
2008年 | 494篇 |
2007年 | 502篇 |
2006年 | 452篇 |
2005年 | 442篇 |
2004年 | 379篇 |
2003年 | 403篇 |
2002年 | 328篇 |
2001年 | 287篇 |
2000年 | 264篇 |
1999年 | 231篇 |
1998年 | 223篇 |
1997年 | 204篇 |
1996年 | 136篇 |
1995年 | 84篇 |
1994年 | 82篇 |
1993年 | 67篇 |
1992年 | 54篇 |
1991年 | 30篇 |
1990年 | 22篇 |
1989年 | 23篇 |
1988年 | 31篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 35篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1980年 | 15篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1974年 | 3篇 |
排序方式: 共有8902条查询结果,搜索用时 625 毫秒
61.
戴滨林 《数学物理学报(A辑)》2007,27(5):935-940
该文对高维非初等Mò'bius变换群进行了研究,得到了一些重要性质,给出了几个关于离散准则和代数收敛性的定理. 相似文献
62.
Florence Newberger 《Geometriae Dedicata》2003,97(1):215-249
The goal of this paper is to provide a tool, the Global Measure Formula, that will facilitate the study of the limit set of discrete geometrically finite groups of isometries of the rank one symmetric spaces. We consider the shadow of a ball from a fixed reference point onto the boundary, and prove a formula that describes the measure of the shadow in terms of the center of the shadowed ball, generalizing a result from real hyperbolic geometry. 相似文献
63.
g1.IntroductionWeconsiderthefollowingfirstorderquasilinearhyperbolicequationswithinternaIdissipa-tlveterm:U, A(U)U. F(U)=o(1.1)whereUeR2isunknownvectorfunction,A(U)is2X2knownsmoothmatrix,F(U)is2X2knownsmoothvectorfunction.Itiswell-knownthatCauchyproblemoftheequations(l.1)hasbeenwidelystudied(Ll-6J),however,theequations(l.1)withperiedicinitialdatahasbeenhardlystudiedandonesfindthatitiscomplicatedforproblemwithperiodicinitialdata.Becausetheperiodicdis-turbanceLlirectlyinfluencesthebounde… 相似文献
64.
E. Sh. Finkel'shtein N. V. Ushakov N. A. Pritula E. A. Andreev N. A. Platé 《Russian Chemical Bulletin》1992,41(1):185-187
The thermally initiated and platinum-catalyzed polymerization of 1-silacyclobutanes with substitutents containing a trimethylsilyl group was carried out. Soluble, high-molecular-weight, heterochain siltrimethylene polymers were obtained, containing trimethylsilyl groups removed from the main chain by various bridges.A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 117912 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 223–225, January, 1992. 相似文献
65.
66.
Ottokar Leminger 《Optical and Quantum Electronics》2002,34(5-6):435-443
Photonic crystals exhibit band gaps, meaning that electromagnetic fields cannot propagate in them for specific ranges of wavelengths
and directions. The calculation of band structure diagrams has been intensively studied and is now well understood. In contrast
to that, so-called wave-vector diagrams (i.e. dispersion surfaces, depicting the loci of all relevant wave vectors at a fixed
wavelength) are less known and used. In principle, they show how the effective index of the structure depends on the direction
of propagation. A method to calculate explicitly wave-vector diagrams for two-dimensional photonic crystals is derived which
leads finally to quadratic eigenvalue problems. Results for square and triangular lattices are presented and some applications
are discussed. 相似文献
67.
The concept of rigid sphericalt-designs was introduced by Bannai. He conjectured that there is a functionf(t, d) such that ifX is a sphericalt design in thed-dimensional Euclidean space so that |X|>f(t, d), theX is non-rigid. Furthermore, he asked to find examples of rigid but not tight sperical designs. In the present article we shall investigate the case whenX is an orbit of a finite reflection group and prove thatX is rigid iff tight for the groupsA
n
,B
n
,C
n
,D
n
,E
6,E
7,F
4,I
3.Research was partially supported by Hungarian National Research fund Grant No. 4267. 相似文献
68.
We study a boundary version of the gauged WZW model with a Poisson–Lie group G as the target. The Poisson–Lie structure of G is used to define the Wess–Zumino term of the action on surfaces with boundary. We clarify the relation of the model to the topological Poisson sigma model with the dual Poisson–Lie group G
* as the target and show that the phase space of the theory on a strip is essentially the Heisenberg double of G introduced by Semenov–Tian–Shansky. 相似文献
69.
A. I. Vanin 《Journal of Applied Spectroscopy》1997,64(2):242-245
Light scattering by groups of spherical particles is considered. It is shown that the structure of the groups and their orientational
distribution can be judged from the spectrum and polarization of the scattered light.
Syktyvkar State University, 55, Oktyabr'skii Ave., Syktyvkar, 167001, Russia. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 2, pp. 228–231, March–April, 1997. 相似文献
70.
Bernard Bialecki 《Numerical Algorithms》1994,8(2):167-184
Cyclic reduction and Fourier analysis-cyclic reduction (FACR) methods are presented for the solution of the linear systems which arise when orthogonal spline collocation with piecewise Hermite bicubics is applied to boundary value problems for certain separable partial differential equations on a rectangle. On anN×N uniform partition, the cyclic reduction and Fourier analysis-cyclic reduction methods requireO(N
2log2
N) andO(N
2log2log2
N) arithmetic operations, respectively. 相似文献