全文获取类型
收费全文 | 2308篇 |
免费 | 184篇 |
国内免费 | 223篇 |
专业分类
化学 | 44篇 |
力学 | 50篇 |
综合类 | 28篇 |
数学 | 1864篇 |
物理学 | 729篇 |
出版年
2024年 | 3篇 |
2023年 | 29篇 |
2022年 | 30篇 |
2021年 | 57篇 |
2020年 | 66篇 |
2019年 | 72篇 |
2018年 | 56篇 |
2017年 | 66篇 |
2016年 | 63篇 |
2015年 | 76篇 |
2014年 | 121篇 |
2013年 | 160篇 |
2012年 | 104篇 |
2011年 | 109篇 |
2010年 | 79篇 |
2009年 | 138篇 |
2008年 | 197篇 |
2007年 | 134篇 |
2006年 | 127篇 |
2005年 | 138篇 |
2004年 | 96篇 |
2003年 | 120篇 |
2002年 | 102篇 |
2001年 | 68篇 |
2000年 | 97篇 |
1999年 | 60篇 |
1998年 | 67篇 |
1997年 | 52篇 |
1996年 | 44篇 |
1995年 | 27篇 |
1994年 | 28篇 |
1993年 | 21篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 9篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1970年 | 1篇 |
1936年 | 3篇 |
排序方式: 共有2715条查询结果,搜索用时 15 毫秒
101.
102.
Examples are given to show that the closest partition distance measure need not agree with the nearest neighbor interchange distance for unordered labeled binary trees. Proposed algorithms for computing the closest partition distance are shown to be of exponential complexity and hence may not be useful in approximating the nearest neighbor interchange distance. 相似文献
103.
104.
105.
Ann M. Hentschel 《Physics in Perspective (PIP)》2005,7(1):107-129
This tour of significant scientific sites in Bern uses the local legacy of its most illustrious scientists, Albert Einstein (1879–1955) and Fritz Houtermans (1903–1966), as its guiding thread through the old town and the university district.Ann M.Hentschel is translator of the correspondence volumes of The Collected Papers of Albert Einstein and is currently employed by the Institute for the History and Philosophy of Science at the University of Bern to write the guide for a city tour of Einsteins old haunts in Bern for the coming jubilee of special relativity in 2005. For the historical companion guidebook, see Hentschel and Grasshoff, Albert Einstein (ref. 4) and the website <. 相似文献
106.
We construct perfect fluid metrics with two symmetries by means of a recently developed geometrical method [1]. The Einstein equations are reduced to a single equation for a conformal factor. Under additional assumptions we obtain new cosmological solutions of Bianchi type II, VI0 and VII0. The solutions depend on an arbitrary function of time, which can be specified in order to satisfy an equation of state. 相似文献
107.
Null isotropy in a spacetime is defined. The relation of null isotropy to the constant curvature and infinitesimal spatial
isotropy is investigated. The influence of null isotropy on conjugate points along null geodesics and curvature singularities
is investigated. 相似文献
108.
Alexander?B.?Balakin Winfried?ZimdahlEmail author 《General Relativity and Gravitation》2005,37(10):1731-1751
The material tensor of linear response in electrodynamics is constructed out of products of two symmetric second rank tensor
fields which in the approximation of geometrical optics and for uniaxial symmetry reduce to “optical” metrics, describing
the phenomenon of birefringence. This representation is interpreted in the context of an underlying internal geometrical structure
according to which the symmetric tensor fields are vectorial elements of an associated two-dimensional space. 相似文献
109.
In this paper we rigorously establish the existence of the mobility coefficient for a tagged particle in a simple symmetric exclusion process with adsorption/desorption of particles, in a presence of an external force field interacting with the particle. The proof is obtained using a perturbative argument. In addition, we show that, for a constant external field, the mobility of a particle equals to the self-diffusivity coefficient, the so-called Einstein relation. The method can be applied to any system where the environment has a Markovian evolution with a fast convergence to equilibrium (spectral gap property). In this context we find a necessary relation between forward and backward velocity for the validity of the Einstein relation. This relation is always satisfied by reversible systems. We provide an example of a non-reversible system, where the Einstein relation is valid.This revised version was published online in March 2005 with corrections to the page numbers. 相似文献
110.
A conformally flat accelerated charge metric is found in an arbitrary dimension D. It is a solution of the Einstein-Maxwell-null fluid equations with a cosmological constant in D ≥ 4 dimensions. When the acceleration is zero, our solution reduces to the Levi-Civita-Bertotti-Robinson metric. We show
that the charge loses its energy, for all dimensions, due to the acceleration. 相似文献