全文获取类型
收费全文 | 15082篇 |
免费 | 509篇 |
国内免费 | 96篇 |
专业分类
化学 | 9826篇 |
晶体学 | 100篇 |
力学 | 323篇 |
综合类 | 2篇 |
数学 | 2233篇 |
物理学 | 3203篇 |
出版年
2023年 | 92篇 |
2022年 | 88篇 |
2021年 | 215篇 |
2020年 | 259篇 |
2019年 | 282篇 |
2018年 | 194篇 |
2017年 | 171篇 |
2016年 | 436篇 |
2015年 | 341篇 |
2014年 | 377篇 |
2013年 | 699篇 |
2012年 | 722篇 |
2011年 | 811篇 |
2010年 | 551篇 |
2009年 | 479篇 |
2008年 | 723篇 |
2007年 | 798篇 |
2006年 | 659篇 |
2005年 | 699篇 |
2004年 | 586篇 |
2003年 | 481篇 |
2002年 | 450篇 |
2001年 | 272篇 |
2000年 | 233篇 |
1999年 | 180篇 |
1998年 | 174篇 |
1997年 | 174篇 |
1996年 | 196篇 |
1995年 | 182篇 |
1994年 | 181篇 |
1993年 | 193篇 |
1992年 | 188篇 |
1991年 | 152篇 |
1990年 | 134篇 |
1989年 | 117篇 |
1988年 | 117篇 |
1987年 | 123篇 |
1986年 | 128篇 |
1985年 | 167篇 |
1984年 | 161篇 |
1983年 | 127篇 |
1982年 | 132篇 |
1981年 | 125篇 |
1980年 | 111篇 |
1979年 | 115篇 |
1978年 | 120篇 |
1977年 | 91篇 |
1975年 | 96篇 |
1974年 | 98篇 |
1973年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
41.
von Eynatten G. Ritter T. Bömmel H. E. Dransfeld K. 《Zeitschrift für Physik B Condensed Matter》1987,65(3):341-345
A new model is presented which explains well the dramatic decrease of the Mössbauer line intensities with raising temperatures for freely dispersed iron microscrystals. In contrast to other theories which consider mainly vibration to be responsible we discuss here the decrease in terms of large amplitude diffusive rotational or translational jumps of the particles. Such diffusive jumps lead — in agreement with the observation — to a strong reduction of the Mössbauer-intensity without broadening the line width in a noticeable way. The typical potential well for a diffusing particle in an equilibrium position is derived quantitatively to be 13 meV. The model might be important also for a new understanding of the dynamics of catalytic clusters either in contact with each other or with larger solid surfaces.Part of this work was supported by the DFG Sonderforschungsbereich 306, Konstanz 相似文献
42.
43.
44.
Jan P. Boroński 《Topology and its Applications》2007,154(18):3156-3166
A set (or a collection of sets) contained in the Euclidean space Rm is symmetric if it is invariant under the antipodal map. Given a symmetric unicoherent polyhedron X (like an n-dimensional cube or a sphere) and an odd real function f defined on vertices of a certain symmetric triangulation of X, we algorithmically construct a connected symmetric separator of X by choosing a subcollection of the triangulation. Each element of the subcollection contains the vertices v and u such that f(v)f(u)?0. 相似文献
45.
46.
Il Bong Jung Alan Lambert Jan Stochel 《Proceedings of the American Mathematical Society》2004,132(8):2291-2302
The concept of backward extension for subnormal weighted shifts is generalized to arbitrary subnormal operators. Several differences and similarities in these contexts are explored, with emphasis on the structure of the underlying measures.
47.
We perform three tests on our proposal to implement diffeomorphism invariance in the non-abelian D0-brane DBI action as a base-point independence constraint between matrix Riemann normal coordinate systems. First, we show that T-duality along an isometry correctly interchanges the potential and kinetic terms in the action. Second, we show that the method to impose base-point independence using an auxiliary dN2-dimensional nonlinear sigma model also works for metrics which are curved along the brane, provided a physical gauge choice is made at the end. Third, we show that without alteration this method is applicable to higher order in velocities. Testing specifically to order 4, we elucidate the range of validity of the symmetrized trace approximation to the non-abelian DBI action. 相似文献
48.
49.
50.
For a dynamical system (X, B, T, μ) we investigate the connections between metric invariants, the rankr(T) and the covering numberF
*(T) and a spectral property for having a simple spectrum. Given a positive integerr≥2, a real numberb, 0<b<1 such thatr·b≥1, we construct examples of systems withr(T)=r, F
*(T)=b and having a simple spectrum. 相似文献