全文获取类型
收费全文 | 7271篇 |
免费 | 468篇 |
国内免费 | 17篇 |
专业分类
化学 | 5576篇 |
晶体学 | 43篇 |
力学 | 150篇 |
数学 | 803篇 |
物理学 | 1184篇 |
出版年
2023年 | 63篇 |
2022年 | 82篇 |
2021年 | 122篇 |
2020年 | 220篇 |
2019年 | 204篇 |
2018年 | 86篇 |
2017年 | 108篇 |
2016年 | 294篇 |
2015年 | 271篇 |
2014年 | 316篇 |
2013年 | 370篇 |
2012年 | 522篇 |
2011年 | 570篇 |
2010年 | 323篇 |
2009年 | 278篇 |
2008年 | 433篇 |
2007年 | 408篇 |
2006年 | 366篇 |
2005年 | 302篇 |
2004年 | 289篇 |
2003年 | 227篇 |
2002年 | 216篇 |
2001年 | 123篇 |
2000年 | 108篇 |
1999年 | 91篇 |
1998年 | 80篇 |
1997年 | 90篇 |
1996年 | 92篇 |
1995年 | 86篇 |
1994年 | 101篇 |
1993年 | 72篇 |
1992年 | 68篇 |
1991年 | 83篇 |
1990年 | 53篇 |
1989年 | 67篇 |
1988年 | 51篇 |
1987年 | 39篇 |
1986年 | 30篇 |
1985年 | 33篇 |
1984年 | 39篇 |
1983年 | 33篇 |
1982年 | 31篇 |
1981年 | 28篇 |
1980年 | 40篇 |
1979年 | 23篇 |
1978年 | 40篇 |
1977年 | 26篇 |
1976年 | 24篇 |
1975年 | 16篇 |
1972年 | 9篇 |
排序方式: 共有7756条查询结果,搜索用时 15 毫秒
11.
Aspects of Generic Entanglement 总被引:4,自引:4,他引:0
Patrick Hayden Debbie W. Leung Andreas Winter 《Communications in Mathematical Physics》2006,265(1):95-117
We study entanglement and other correlation properties of random states in high-dimensional bipartite systems. These correlations
are quantified by parameters that are subject to the ``concentration of measure' phenomenon, meaning that on a large-probability
set these parameters are close to their expectation. For the entropy of entanglement, this has the counterintuitive consequence
that there exist large subspaces in which all pure states are close to maximally entangled. This, in turn, implies the existence
of mixed states with entanglement of formation near that of a maximally entangled state, but with negligible quantum mutual
information and, therefore, negligible distillable entanglement, secret key, and common randomness. It also implies a very
strong locking effect for the entanglement of formation: its value can jump from maximal to near zero by tracing over a number
of qubits negligible compared to the size of the total system. Furthermore, such properties are generic. Similar phenomena
are observed for random multiparty states, leading us to speculate on the possibility that the theory of entanglement is much
simplified when restricted to asymptotically generic states. Further consequences of our results include a complete derandomization
of the protocol for universal superdense coding of quantum states. 相似文献
12.
13.
14.
We investigate heteroclinic orbits between equilibria and rotating waves for scalar semilinear parabolic reaction-advection-diffusion equations with periodic boundary conditions. Using zero number properties of the solutions and the phase shift equivariance of the equation, we establish a necessary and sufficient condition for the existence of a heteroclinic connection between any pair of hyperbolic equilibria or rotating waves. 相似文献
15.
16.
17.
The contributions to the coefficient functions of the quark and the mixed quark-gluon condensate to mesonic correlators are calculated for the first time to all orders in the quark masses, and to lowest order in the strong coupling constant. Existing results on the coefficient functions of the unit operator and the gluon condensate are reviewed. The proper factorization of short- and long-distance contributions in the operator product expansion is discussed in detail. It is found that to accomplish this task rigorously the operator product expansion has to be performed in terms ofnon-normal-ordered condensates. The resulting coefficient functions are improved with the help of the renormalization group. The scale invariant combination of dimension 5 operators, including mixing with the mass operator, which is needed for the renormalization group improvement, is calculated in the leading order.Supported by the German Bundesministerium für Forschung und Technologie, under the contract 06 TM 761 相似文献
18.
Peter Karduck Norbert Ammann Hans Günter Esser Jörg Winter 《Fresenius' Journal of Analytical Chemistry》1991,341(5-6):315-319
Summary The first wall of the fusion device TEXTOR at the Forschungszentrum Jülich has been coated in situ with an amorphous hydrogen rich carbon/boron film (a-C/B:H) which reduces plasma impurities caused by the plasma surface interaction. The results of the coating process of the 35 m2 large inner wall surface have been controlled by a recently developed modification of the quantitative electron probe microanalysis, which has been applied to 12 samples from specified positions inside the tokamak. The quantification itself is based on a Monte Carlo simulation of electron trajectories providing very accurate results for X-ray intensities emitted by elements present in the electron bombarded sample. The Monte Carlo results are used in the present work to calibrate the measured X-ray intensities emitted by boron and carbon from the a-C/B:H layers deposited on pure silicon substrates. As a result the total deposited mass of the layer per area unit as well as the composition of the layers (except hydrogen) could be determined very accurately. The relative errors were less than 7%. The limit of detectability were found to be in the range of one monolayer for boron as well as for carbon. 相似文献
19.
We derive a moderate deviation principle for the lower tail probabilities of the length of a longest increasing subsequence in a random permutation. It refers to the regime between the lower tail large deviation regime and the central limit regime. The present article together with the upper tail moderate deviation principle in Ref. 12 yields a complete picture for the whole moderate deviation regime. Other than in Ref. 12, we can directly apply estimates by Baik, Deift, and Johansson, who obtained a (non-standard) Central Limit Theorem for the same quantity. 相似文献
20.
Matthias Kriesell 《Graphs and Combinatorics》2002,18(1):133-146
Let k≤n be positive integers. A finite, simple, undirected graph is called k-critically n-connected, or, briefly, an (n,k)-graph, if it is noncomplete and n-connected and the removal of any set X of at most k vertices results in a graph which is not (n−|X|+1)-connected. We present some new results on the number of vertices of an (n,k)-graph, depending on new estimations of the transversal number of a uniform hypergraph with a large independent edge set.
Received: April 14, 2000 Final version received: May 8, 2001 相似文献