全文获取类型
收费全文 | 599篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 354篇 |
晶体学 | 6篇 |
力学 | 16篇 |
数学 | 33篇 |
物理学 | 198篇 |
出版年
2021年 | 4篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 34篇 |
2012年 | 29篇 |
2011年 | 40篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 20篇 |
2007年 | 15篇 |
2006年 | 28篇 |
2005年 | 34篇 |
2004年 | 29篇 |
2003年 | 21篇 |
2002年 | 17篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 20篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1931年 | 2篇 |
1897年 | 3篇 |
排序方式: 共有607条查询结果,搜索用时 31 毫秒
1.
Michael Carr 《Topology and its Applications》2006,153(12):2155-2168
Given a graph Γ, we construct a simple, convex polytope, dubbed graph-associahedra, whose face poset is based on the connected subgraphs of Γ. This provides a natural generalization of the Stasheff associahedron and the Bott-Taubes cyclohedron. Moreover, we show that for any simplicial Coxeter system, the minimal blow-ups of its associated Coxeter complex has a tiling by graph-associahedra. The geometric and combinatorial properties of the complex as well as of the polyhedra are given. These spaces are natural generalizations of the Deligne-Knudsen-Mumford compactification of the real moduli space of curves. 相似文献
2.
3.
Images of the surface ordering of 4-n-octyl-4'-cyanobiphenyl, a room temperature smectic liquid crystal deposited upon graphite, have been obtained by scanning tunnelling microscopy. The microscope was operated in air using the constant-current mode. Under certain tunnelling conditions it has been possible to resolve both the aliphatic and aromatic parts of the molecule, and to observe individual benzene rings. Two previously unreported conformations have been observed: an overlapping bilayer structure with spacing 3.7 nm, and a monolayer structure with spacing 2.4 nm. The latter structure may represent the first visual evidence for a surface polar ordered structure. 相似文献
4.
5.
We consider the equation in question on the interval 0 ≦ x ≦ 1 having Neumann boundary conditions, with f(u) = F(u), where F is a double well energy density with equal minima at u = ±1. The only stable states of the system are patternless constant solutions. But given two-phase initial data, a pattern of interfacial layers typically forms far out of equilibrium. The ensuing nonlinear relaxation process is extremely slow: patterns persist for exponentially long times proportional to exp{A±l/?, where A = F(±1) and l is the minimum distance between layers. Physically, a tiny potential jump across a layer drives its motion. We prove the existence and persistence of these metastable patterns, and characterise accurately the equations governing their motion. The point of view is reminiscent of center manifold theory: a manifold parametrising slowly evolving states is introduced, a neighbourhood is shown to be normally attracting, and the parallel flow is characterised to high relative accuracy. Proofs involve a detailed study of the Dirichlet problem, spectral gap analysis, and energy estimates. 相似文献
6.
7.
8.
9.
10.
B. Carré P. d'Oliveira M. Ferray P. Fournier F. Gounand D. Cubaynes J. -M. Bizau F. J. Wuilleumier 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1990,15(2):117-132
Resonant photoionization in thenl outer-shell of 2p 6 nl excited sodium is studied between 32.50 and 33.50 eV. Resonances are of the type 2p 6 nl → 2p 5 3snl → 2p 6 ελ, i.e. corresponding to the excitation of a 2p core-electron to a 3s orbital. Experimental technique combines laser and synchrotron radiation for exciting sequentially sodium atoms. The main features of the resonances — energies and total oscillator strengths — are measured or estimated. From the results, one concludes that the valence electron is almost decoupled from the core, with respect to the core excitation. 相似文献