全文获取类型
收费全文 | 6710篇 |
免费 | 485篇 |
国内免费 | 555篇 |
专业分类
化学 | 608篇 |
晶体学 | 4篇 |
力学 | 510篇 |
综合类 | 98篇 |
数学 | 5091篇 |
物理学 | 1439篇 |
出版年
2024年 | 15篇 |
2023年 | 59篇 |
2022年 | 78篇 |
2021年 | 117篇 |
2020年 | 161篇 |
2019年 | 171篇 |
2018年 | 170篇 |
2017年 | 170篇 |
2016年 | 181篇 |
2015年 | 141篇 |
2014年 | 294篇 |
2013年 | 527篇 |
2012年 | 274篇 |
2011年 | 348篇 |
2010年 | 291篇 |
2009年 | 364篇 |
2008年 | 443篇 |
2007年 | 421篇 |
2006年 | 374篇 |
2005年 | 355篇 |
2004年 | 319篇 |
2003年 | 316篇 |
2002年 | 299篇 |
2001年 | 222篇 |
2000年 | 191篇 |
1999年 | 203篇 |
1998年 | 199篇 |
1997年 | 151篇 |
1996年 | 132篇 |
1995年 | 96篇 |
1994年 | 83篇 |
1993年 | 64篇 |
1992年 | 55篇 |
1991年 | 44篇 |
1990年 | 51篇 |
1989年 | 46篇 |
1988年 | 34篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 34篇 |
1984年 | 36篇 |
1983年 | 21篇 |
1982年 | 28篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 28篇 |
1978年 | 15篇 |
1977年 | 15篇 |
1976年 | 12篇 |
1973年 | 8篇 |
排序方式: 共有7750条查询结果,搜索用时 93 毫秒
51.
Motivated by the central limit problem for convex bodies, we study normal approximation of linear functionals of high-dimensional
random vectors with various types of symmetries. In particular, we obtain results for distributions which are coordinatewise
symmetric, uniform in a regular simplex, or spherically symmetric. Our proofs are based on Stein’s method of exchangeable
pairs; as far as we know, this approach has not previously been used in convex geometry. The spherically symmetric case is
treated by a variation of Stein’s method which is adapted for continuous symmetries.
This work was done while at Stanford University. 相似文献
52.
Yu-hai WU~ 《中国科学A辑(英文版)》2007,50(7):925-940
This paper concerns the number and distributions of limit cycles in a Z_2-equivariant quintic planar vector field.25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation.It can be concluded that H(5)≥25=5~2, where H(5)is the Hilbert number for quintic polynomial systems.The results obtained are useful to study the weakened 16th Hilbert problem. 相似文献
53.
Prot Pakoński Gregor Tanner Karol Życzkowski 《Journal of statistical physics》2003,111(5-6):1331-1352
Any directed graph G with N vertices and J edges has an associated line-graph L(G) where the J edges form the vertices of L(G). We show that the non-zero eigenvalues of the adjacency matrices are the same for all graphs of such a family L
n
(G). We give necessary and sufficient conditions for a line-graph to be quantisable and demonstrate that the spectra of associated quantum propagators follow the predictions of random matrices under very general conditions. Line-graphs may therefore serve as models to study the semiclassical limit (of large matrix size) of a quantum dynamics on graphs with fixed classical behaviour. 相似文献
54.
We consider the estimation of multivariate regression functions r(x1,…,xd) and their partial derivatives up to a total order p1 using high-order local polynomial fitting. The processes {Yi,Xi} are assumed to be (jointly) associated. Joint asymptotic normality is established for the estimates of the regression function r and all its partial derivatives up to the total order p. Expressions for the bias and variance/covariance matrix (of the asymptotic distribution) are given. 相似文献
55.
56.
57.
Weconsiderthequadraticsystemoftype(I)m=0acordingtotheclasificationof[1].Withoutlosofgenerality,wemayasumethatthesystemistaken... 相似文献
58.
Hans C. Fogedby 《Journal of statistical physics》1992,69(1-2):411-425
We elaborate in some detail on a new phase space approach to complexity, due to Y.-C. Zhang. We show in particular that the connection between maximal complexity and power law noise or correlations can be derived from a simple variational principle. For a 1D signal we find 1/f noise, in accordance with Zhang. 相似文献
59.
60.
讨论了微分方程组 dx/dt=-y(1 -ax2 n) +bx-cx2 n+ 1,dy/dt=x(1 -ax2 n) ,并且给出了其极限环存在唯一的条件 . 相似文献