全文获取类型
收费全文 | 11534篇 |
免费 | 256篇 |
国内免费 | 275篇 |
专业分类
化学 | 1432篇 |
晶体学 | 31篇 |
力学 | 77篇 |
综合类 | 17篇 |
数学 | 9713篇 |
物理学 | 795篇 |
出版年
2023年 | 19篇 |
2022年 | 47篇 |
2021年 | 26篇 |
2020年 | 42篇 |
2019年 | 247篇 |
2018年 | 281篇 |
2017年 | 151篇 |
2016年 | 101篇 |
2015年 | 122篇 |
2014年 | 290篇 |
2013年 | 713篇 |
2012年 | 350篇 |
2011年 | 671篇 |
2010年 | 605篇 |
2009年 | 901篇 |
2008年 | 870篇 |
2007年 | 872篇 |
2006年 | 662篇 |
2005年 | 428篇 |
2004年 | 382篇 |
2003年 | 299篇 |
2002年 | 235篇 |
2001年 | 218篇 |
2000年 | 232篇 |
1999年 | 255篇 |
1998年 | 255篇 |
1997年 | 178篇 |
1996年 | 244篇 |
1995年 | 251篇 |
1994年 | 251篇 |
1993年 | 193篇 |
1992年 | 171篇 |
1991年 | 125篇 |
1990年 | 142篇 |
1989年 | 142篇 |
1988年 | 91篇 |
1987年 | 95篇 |
1986年 | 105篇 |
1985年 | 139篇 |
1984年 | 110篇 |
1983年 | 57篇 |
1982年 | 94篇 |
1981年 | 67篇 |
1980年 | 78篇 |
1979年 | 58篇 |
1978年 | 60篇 |
1977年 | 39篇 |
1976年 | 33篇 |
1975年 | 24篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
21.
Zhaoyang Yin 《Monatshefte für Mathematik》2004,141(4):337-344
We prove under quite general assumptions the existence of a bounded positive solution to the semilinear Schrödinger equation in a two-dimensional exterior domain. 相似文献
22.
Walter Benz 《Monatshefte für Mathematik》2004,141(1):1-10
The lines of euclidean and hyperbolic geometries are characterized as metric lines in the sense of Blumenthal–Menger, and the lines of spherical and elliptic geometry as periodic ones. In euclidean geometries there do not exist periodic lines. 相似文献
23.
In this paper, we consider Girsanov transforms of pure jump type for discontinuous Markov processes. We show that, under some quite natural conditions, the Green functions of the Girsanov transformed process are comparable to those of the original process. As an application of the general results, the drift transform of symmetric stable processes is studied in detail. In particular, we show that the relativistic α-stable process in a bounded C1,1-smooth open set D can be obtained from symmetric α-stable process in D through a combination of a pure jump Girsanov transform and a Feynman-Kac transform. From this, we deduce that the Green functions for these two processes in D are comparable. 相似文献
24.
Summary. We study a diffusion model of an interacting particles system with general drift and diffusion coefficients, and electrostatic
inter-particles repulsion. More precisely, the finite particle system is shown to be well defined thanks to recent results
on multivalued stochastic differential equations (see [2]), and then we consider the behaviour of this system when the number
of particles goes to infinity (through the empirical measure process). In the particular case of affine drift and constant diffusion coefficient,
we prove that a limiting measure-valued process exists and is the unique solution of a deterministic PDE. Our treatment of
the convergence problem (as ) is partly similar to that of T. Chan [3] and L.C.G. Rogers - Z. Shi [5], except we consider here a more general case allowing
collisions between particles, which leads to a second-order limiting PDE.
Received: 5 August 1996 / In revised form: 17 October 1996 相似文献
25.
Dorina Mitrea Marius Mitrea Jill Pipher 《Journal of Fourier Analysis and Applications》1997,3(2):131-192
We study boundary value problems for the time-harmonic form of the Maxwell equations, as well as for other related systems
of equations, on arbitrary Lipschitz domains in the three-dimensional Euclidean space. The main goal is to develop the corresponding
theory for Lp-integrable bounday data for optimal values of p's. We also discuss a number of relevant applications in electromagnetic scattering. 相似文献
26.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions.
In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation
solutions.
Accepted 27 February 1996 相似文献
27.
Oleg Borodin 《Combinatorica》1993,13(1):121-125
The weight of an edge in a graph is the sum of the degrees of its end-vertices. It is proved that in each 3-polytope there exists either an edge of weight at most 13 for which both incident faces are triangles, or an edge of weight at most 10 which is incident with a triangle, or else an edge of weight at most 8. All the bounds 13, 10, and 8 are sharp and attained independently of each other. 相似文献
28.
29.
Summary In the present paper we study truncated projections for the fanbeam geometry in computerized tomography. First we derive consistency conditions for the divergent beam transform. Then we study a singular value decomposition for the case where only the interior rays in the fan are provided, as for example in region-of-interest tomography. We show that the high angular frequency components of the searched-for densities are well determined and we present reconstructions from real data where the missing information is approximated based on the singular value decomposition.The work of the authors was supported by the Deutsche Forschungsgemeinschaft under grant Lo 310/2-4 相似文献
30.
This paper establishes a link between a generalized matrix Matsumoto-Yor (MY) property and the Wishart distribution. This link highlights certain conditional independence properties within blocks of the Wishart and leads to a new characterization of the Wishart distribution similar to the one recently obtained by Geiger and Heckerman but involving independences for only three pairs of block partitionings of the random matrix.In the process, we obtain two other main results. The first one is an extension of the MY independence property to random matrices of different dimensions. The second result is its converse. It extends previous characterizations of the matrix generalized inverse Gaussian and Wishart seen as a couple of distributions.We present two proofs for the generalized MY property. The first proof relies on a new version of Herz's identity for Bessel functions of matrix arguments. The second proof uses a representation of the MY property through the structure of the Wishart. 相似文献