全文获取类型
收费全文 | 3577篇 |
免费 | 463篇 |
国内免费 | 278篇 |
专业分类
化学 | 391篇 |
晶体学 | 41篇 |
力学 | 472篇 |
综合类 | 62篇 |
数学 | 2119篇 |
物理学 | 1233篇 |
出版年
2024年 | 4篇 |
2023年 | 40篇 |
2022年 | 58篇 |
2021年 | 82篇 |
2020年 | 73篇 |
2019年 | 114篇 |
2018年 | 110篇 |
2017年 | 119篇 |
2016年 | 96篇 |
2015年 | 106篇 |
2014年 | 172篇 |
2013年 | 410篇 |
2012年 | 165篇 |
2011年 | 215篇 |
2010年 | 179篇 |
2009年 | 221篇 |
2008年 | 234篇 |
2007年 | 239篇 |
2006年 | 199篇 |
2005年 | 191篇 |
2004年 | 158篇 |
2003年 | 171篇 |
2002年 | 159篇 |
2001年 | 138篇 |
2000年 | 112篇 |
1999年 | 96篇 |
1998年 | 92篇 |
1997年 | 72篇 |
1996年 | 66篇 |
1995年 | 37篇 |
1994年 | 37篇 |
1993年 | 17篇 |
1992年 | 30篇 |
1991年 | 21篇 |
1990年 | 11篇 |
1989年 | 5篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1971年 | 1篇 |
1957年 | 2篇 |
1936年 | 1篇 |
排序方式: 共有4318条查询结果,搜索用时 15 毫秒
11.
Daniel Maerten 《Annals of Global Analysis and Geometry》2007,32(4):391-414
We prove a Penrose-like inequality for the mass of a large class of constant mean curvature (CMC) asymptotically flat n-dimensional spin manifolds which satisfy the dominant energy condition and have a future converging, or past converging compact
and connected boundary of non-positive mean curvature and of positive Yamabe invariant. We prove that for every n ≥ 3 the mass is bounded from below by an expression involving the norm of the linear momentum, the volume of the boundary,
dimensionless geometric constants and some normalized Sobolev ratio. 相似文献
12.
Hui Ping Zhang 《数学学报(英文版)》2006,22(3):945-950
In this paper, we first define a kind of pseudo–distance function and annulus domain on Riemann surfaces, then prove the Hadamard
Theorem and the Borel–Carathéodory Theorem on any Riemann surfaces.
Supported by NSFC 10501052 相似文献
13.
有界连通区域上Dirichlet空间及其算子 总被引:1,自引:0,他引:1
本文主要讨论了有界连通区域Dirichlet空间上Toeplitz算子的Fredholm性质,计算了符号在C1中的Toeplitz算子的本性谱和Fredholm指标. 相似文献
14.
Masanobu Haraguchi David F. P. Pile Toshihiro Okamoto Masuo Fukui Dmitri K. Gramotnev 《Optical Review》2006,13(4):228-230
We have numerically shown the existence of coupled wedge plasmons (CWPs) which propagates along a nano gap of a twin metal
wedge. The CWPs are formed by wedge plasmons which can interact with each other. The dispersion relations of the wavenumber,
propagation distance, and beam area of CWPs, are described and show that the characteristics of CWPs are similar to those
of wedge plasmons and of gap plasmons. We also propose a new plasmon waveguide composed of twin metal wedges with a nano gap. 相似文献
15.
We study the spectral properties of a large class of compact flat Riemannian manifolds of dimension 4, namely, those whose
corresponding Bieberbach groups have the canonical lattice as translation lattice. By using the explicit expression of the
heat trace of the Laplacian acting on p-forms, we determine all p-isospectral and L-isospectral pairs and we show that in this class of manifolds, isospectrality on functions and isospectrality on p-forms for all values of p are equivalent to each other. The list shows for any p, 1 ≤ p ≤ 3, many p-isospectral pairs that are not isospectral on functions and have different lengths of closed geodesics. We also determine
all length isospectral pairs (i.e. with the same length multiplicities), showing that there are two weak length isospectral
pairs that are not length isospectral, and many pairs, p-isospectral for all p and not length isospectral.
Mathematics Subject Classifications (2000): 58J53, 58C22, 20H15. 相似文献
16.
R.S. Kraußhar 《Journal of Mathematical Analysis and Applications》2007,325(1):359-376
In this paper we study Clifford and harmonic analysis on some examples of conformal flat manifolds that have a spinor structure, or more generally, at least a pin structure. The examples treated here are manifolds that can be parametrized by U/Γ where U is a subdomain of either Sn or Rn and Γ is a Kleinian group acting discontinuously on U. The examples studied here include RPn and the Hopf manifolds S1×Sn−1. Also some hyperbolic manifolds will be treated. Special kinds of Clifford-analytic automorphic forms associated to the different choices of Γ are used to construct explicit Cauchy kernels, Cauchy integral formulas, Green's kernels and formulas together with Hardy spaces and Plemelj projection operators for Lp spaces of hypersurfaces lying in these manifolds. 相似文献
17.
This paper has demonstrated that the Schwartz alternating process must converge if D-N alternating process has converged. Its technique is that the overlapping regions in Schwartz alternating process are considered as independent domains, then Schwartz alternating process could be transformed into D-N alter-nating process. Finally the convergence estimation of Schwartz alternating process could be obtained. The results show that its convergence rate is same as that of D-N alternating process. 相似文献
18.
Tiziana Cardinali Raffaella Servadei 《Proceedings of the American Mathematical Society》2004,132(8):2339-2349
In this paper we obtain the existence of periodic solutions for nonlinear ``invariance' problems monitored by impulsive differential inclusions subject to impulse effects.
19.
J. T. Haslinger K. Kunisch G. Peichl 《Computational Optimization and Applications》2003,26(3):231-251
This contribution deals with an efficient method for the numerical realization of the exterior and interior Bernoulli free boundary problems. It is based on a shape optimization approach. The state problems are solved by a fictitious domain solver using boundary Lagrange multipliers. 相似文献
20.
We study a class of shape optimization problems for semi-linear elliptic equations with Dirichlet boundary conditions in smooth
domains in ℝ2. A part of the boundary of the domain is variable as the graph of a smooth function. The problem is equivalently reformulated
on a fixed domain. Continuity of the solution to the state equation with respect to domain variations is shown. This is used
to obtain differentiability in the general case, and moreover a useful formula for the gradient of the cost functional in
the case where the principal part of the differential operator is the Laplacian.
Online publication 23 January 2004. 相似文献