全文获取类型
收费全文 | 12046篇 |
免费 | 515篇 |
国内免费 | 48篇 |
专业分类
化学 | 8708篇 |
晶体学 | 211篇 |
力学 | 174篇 |
数学 | 1826篇 |
物理学 | 1690篇 |
出版年
2023年 | 92篇 |
2022年 | 113篇 |
2021年 | 178篇 |
2020年 | 263篇 |
2019年 | 225篇 |
2018年 | 155篇 |
2017年 | 131篇 |
2016年 | 445篇 |
2015年 | 405篇 |
2014年 | 432篇 |
2013年 | 538篇 |
2012年 | 721篇 |
2011年 | 770篇 |
2010年 | 543篇 |
2009年 | 447篇 |
2008年 | 705篇 |
2007年 | 621篇 |
2006年 | 592篇 |
2005年 | 605篇 |
2004年 | 520篇 |
2003年 | 385篇 |
2002年 | 350篇 |
2001年 | 186篇 |
2000年 | 157篇 |
1999年 | 177篇 |
1998年 | 133篇 |
1997年 | 180篇 |
1996年 | 137篇 |
1995年 | 132篇 |
1994年 | 137篇 |
1993年 | 123篇 |
1992年 | 111篇 |
1991年 | 83篇 |
1990年 | 61篇 |
1989年 | 99篇 |
1988年 | 76篇 |
1987年 | 62篇 |
1985年 | 81篇 |
1984年 | 58篇 |
1983年 | 53篇 |
1982年 | 74篇 |
1981年 | 51篇 |
1980年 | 60篇 |
1979年 | 51篇 |
1978年 | 52篇 |
1959年 | 69篇 |
1958年 | 69篇 |
1956年 | 83篇 |
1955年 | 62篇 |
1954年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The finite-size corrections, central chargesc, and scaling dimensionsx of tricritical hard squares and critical hard hexagons are calculated analytically. This is achieved by solving the special functional equation or inversion identity satisfied by the commuting row transfer matrices of these lattice models at criticality. The results are expressed in terms of Rogers dilogarithms. For tricritical hard squares we obtainc=7/10,x=3/40, 1/5, 7/8, 6/5 and for hard hexagons we obtainc=4/5,x=2/15, 4/5, 17/15, 4/3, 9/5, in accord with the predictions of conformal and modular invariance. 相似文献
2.
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
3.
4.
Arno Jüschke Johannes Jahn Andreas Kirsch 《Computational Optimization and Applications》1997,7(3):261-276
In this paper we consider a special optimization problem withtwo objectives which arises in antenna theory. It is shown that thisabstract bicriterial optimization problem has at least one solution.Discretized versions of this problem are also discussed, and therelationships between these finite dimensional problems and the infinitedimensional problem are investigated. Moreover, we presentnumerical results for special parameters using a multiobjectiveoptimization method. 相似文献
5.
T. Engel M. Würtz S. Borneis St. Becker I. Klaft A. Kohl T. Kühl F. Laeri D. Marx K. Meier R. Neumann F. Schmitt P. Seelig L. Völker 《Hyperfine Interactions》1997,108(1-3):251-258
Laser spectroscopy at storage rings often suffers from a limited resolution due to Doppler-broadened resonances. Broadening
is caused by the velocity spread of the ions stored in the beam. In the following, the present status of our work on laser
systems specialized on the specific needs of laser spectroscopy at storage rings is reported.
Two pulsed laser systems were developed. One is a dye laser whose spectral bandwidth can be switched by inserting different
Littrow-prisms into the resonator. An increase in bandwidth up to a factor of 45 was achieved. This laser was used for fast
qualitative scans and high resolution measurements. The other laser system is a Nd : YAG laser pumped optical parametric oscillator.
It is a tunable laser system covering the spectral range from 410 to 4000 nm. Furthermore, a continuous wave laser with a
frequency shifted feedback cavity is described. It shows broadband emission with an adjustable bandwidth of up to 4.5 GHz.
This laser can be advantageous for laser cooling of ion beams.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
7.
8.
Summary We study a countable system of interacting diffusions on the interval [0,1], indexed by a hierarchical group. A particular choice of the interaction guaranties, we are in the diffusive clustering regime. This means clusters of components with values either close to 0 or close to 1 grow on various different scales. However, single components oscillate infinitely often between values close to 0 and close to 1 in such a way that they spend fraction one of their time together and close to the boundary. The processes in the whole class considered and starting with a shift-ergodic initial law have the same qualitative properties (universality). 相似文献
9.
We construct cellular homotopy theories for categories of simplicial presheaves on small Grothendieck sites and discuss applications to the motivic homotopy category of Morel and Voevodsky. 相似文献
10.
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