全文获取类型
收费全文 | 3904篇 |
免费 | 219篇 |
国内免费 | 17篇 |
专业分类
化学 | 2698篇 |
晶体学 | 9篇 |
力学 | 139篇 |
数学 | 678篇 |
物理学 | 616篇 |
出版年
2023年 | 46篇 |
2022年 | 48篇 |
2021年 | 92篇 |
2020年 | 88篇 |
2019年 | 115篇 |
2018年 | 76篇 |
2017年 | 56篇 |
2016年 | 167篇 |
2015年 | 138篇 |
2014年 | 141篇 |
2013年 | 227篇 |
2012年 | 330篇 |
2011年 | 382篇 |
2010年 | 209篇 |
2009年 | 191篇 |
2008年 | 293篇 |
2007年 | 261篇 |
2006年 | 244篇 |
2005年 | 199篇 |
2004年 | 178篇 |
2003年 | 135篇 |
2002年 | 108篇 |
2001年 | 47篇 |
2000年 | 48篇 |
1999年 | 35篇 |
1998年 | 22篇 |
1997年 | 26篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1929年 | 4篇 |
排序方式: 共有4140条查询结果,搜索用时 15 毫秒
11.
Nicolas Bergeron 《Mathematische Zeitschrift》2002,241(1):101-125
Let M be an arithmetic hyperbolic manifold and be a codimension 1 geodesic cycle. In this paper, we study the asymptotic growth of the -norm of the lifts of F in the congruence tower above M. We obtain an explicit value for the growth rate of this norm. In particular, we provide a new proof of a celebrated result
of Millson [Mi] on the homology of the arithmetic hyperbolic manifolds. The method is quite general and gives a new way of
getting non zero homology classes in certain locally symmetric spaces.
Received: 20 April 2001; in final form: 26 September 2001 / Published online: 28 February 2002 相似文献
12.
We study nonlinear Schrödinger equations, posed on a three dimensional Riemannian manifold M. We prove global existence of strong H1 solutions on M=S3 and M=S2×S1 as far as the nonlinearity is defocusing and sub-quintic and thus we extend results of Ginibre, Velo and Bourgain who treated the cases of the Euclidean space R3 and the torus T3=R3/Z3 respectively. The main ingredient in our argument is a new set of multilinear estimates for spherical harmonics. 相似文献
13.
14.
15.
This paper deals with the unsupervised classification of univariate observations. Given a set of observations originating from a K-component mixture, we focus on the estimation of the component expectations. We propose an algorithm based on the minimization of the “K-product” (KP) criterion we introduced in a previous work. We show that the global minimum of this criterion can be reached by first solving a linear system then calculating the roots of some polynomial of order K. The KP global minimum provides a first raw estimate of the component expectations, then a nearest-neighbour classification enables to refine this estimation. Our method’s relevance is finally illustrated through simulations of various mixtures. When the mixture components do not strongly overlap, the KP algorithm provides better estimates than the Expectation-Maximization algorithm. 相似文献
16.
This Note addresses the derivation of an improved On-Surface Radiation Condition for the numerical solution of the exterior Helmholtz equation at high-frequencies. This condition is built as an approximation of the Neumann-to-Dirichlet map by using a local regularization of its principal classical symbol in the gliding zone for modelling the creeping waves. The numerical simulation of this pseudodifferential operator is efficiently realized with a linear cost according to the dimension of the boundary element approximation space using suitable complex Padé approximants. A numerical example is provided. To cite this article: X. Antoine et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
17.
A technique is described for the measurement of all components of mean velocity and Reynolds stresses, in a complex turbulent flow where achieving coincidence data acquisition is difficult. The method is based on data recorded using four orientations of the laser probe. It is shown that the measurement errors are not the same for all the components of the Reynolds tensor, but they are sufficiently small to give a good accuracy. An application to a turbomachinery flow is given to illustrate the method. 相似文献
18.
19.
20.
We study property (T) and the fixed-point property for actions on L
p
and other Banach spaces. We show that property (T) holds when L
2 is replaced by L
p
(and even a subspace/quotient of L
p
), and that in fact it is independent of 1≤p<∞. We show that the fixed-point property for L
p
follows from property (T) when 1<p< 2+ε. For simple Lie groups and their lattices, we prove that the fixed-point property for L
p
holds for any 1< p<∞ if and only if the rank is at least two. Finally, we obtain a superrigidity result for actions of irreducible lattices
in products of general groups on superreflexive spaces.
Bader partially supported by ISF grant 100146; Furman partially supported by NSF grants DMS-0094245 and DMS-0604611; Gelander
partially supported by NSF grant DMS-0404557 and BSF grant 2004010; Monod partially supported by FNS (CH) and NSF (US). 相似文献