全文获取类型
收费全文 | 405篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 146篇 |
力学 | 11篇 |
数学 | 150篇 |
物理学 | 115篇 |
出版年
2023年 | 3篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 16篇 |
2014年 | 13篇 |
2013年 | 23篇 |
2012年 | 17篇 |
2011年 | 12篇 |
2010年 | 14篇 |
2009年 | 23篇 |
2008年 | 21篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1968年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有422条查询结果,搜索用时 15 毫秒
51.
52.
53.
Let X_1 and X_2 be two compact connected strongly pseudoconvex embeddable Cauchy-Riemann(CR) manifolds of dimensions 2m-1 and 2n-1 in C~(m+1)and C~(n+1), respectively. We introduce the ThomSebastiani sum X = X_1 ⊕X_2which is a new compact connected strongly pseudoconvex embeddable CR manifold of dimension 2m+2n+1 in C~(m+n+2). Thus the set of all codimension 3 strongly pseudoconvex compact connected CR manifolds in Cn+1for all n 2 forms a semigroup. X is said to be an irreducible element in this semigroup if X cannot be written in the form X_1 ⊕ X_2. It is a natural question to determine when X is an irreducible CR manifold. We use Kohn-Rossi cohomology groups to give a necessary condition of the above question. Explicitly,we show that if X = X_1 ⊕ X_2, then the Kohn-Rossi cohomology of the X is the product of those Kohn-Rossi cohomology coming from X_1 and X_2 provided that X_2 admits a transversal holomorphic S~1-action. 相似文献
54.
We consider random d‐regular graphs on N vertices, with degree d at least (log N)4. We prove that the Green's function of the adjacency matrix and the Stieltjes transform of its empirical spectral measure are well approximated by Wigner's semicircle law, down to the optimal scale given by the typical eigenvalue spacing (up to a logarithmic correction). Aside from well‐known consequences for the local eigenvalue distribution, this result implies the complete (isotropic) delocalization of all eigenvectors and a probabilistic version of quantum unique ergodicity.© 2017 Wiley Periodicals, Inc. 相似文献
55.
Consider the Dyson Brownian motion with parameter β, where β=1,2,4 corresponds to the eigenvalue flows for the eigenvalues of symmetric, hermitian and quaternion self-dual ensembles.
For any β≥1, we prove that the relaxation time to local equilibrium for the Dyson Brownian motion is bounded above by N
−ζ for some ζ>0. The proof is based on an estimate of the entropy flow of the Dyson Brownian motion w.r.t. a “pseudo equilibrium
measure”. As an application of this estimate, we prove that the eigenvalue spacing statistics in the bulk of the spectrum
for N×N symmetric Wigner ensemble is the same as that of the Gaussian Orthogonal Ensemble (GOE) in the limit N→∞. The assumptions on the probability distribution of the matrix elements of the Wigner ensemble are a subexponential decay
and some minor restriction on the support. 相似文献
56.
57.
Mirror Symmetry, Picard-Fuchs equations and instanton corrected Yukawa couplings are discussed within the framework of toric geometry. It allows to establish mirror symmetry of Calabi-Yau spaces for which the mirror manifold had been unavailable in previous constructions. Mirror maps and Yukawa couplings are explicitly given for several examples with two and three moduli.On leave of absence from Dept. of Math., Toyama Univ., Toyama 930, Japan (address after Sept. 1, 1993)Address after Oct. 1, 1993: Dept. of Math., Harvard Univ., Cambridge, MA 02138, USA. after April 1, 1994: CERN, Theory Division, CH-1211 Geneva 23, Switzerland 相似文献
58.
59.
Making use of the idea of synthetic discriminant functions (SDF), a simple way to synthesize a shift, rotation and limited size correlation filter is proposed. The SDF is synthesized by superimposing four 2nd order circular harmonics of a training reference pattern in 4 different sizes. Computer simulation experiments have shown that the filter is indeed shift, full rotation and limited size invariant over a size range from 1 to 1.82. The invariant range can be increased if more training patterns are used. 相似文献
60.