全文获取类型
收费全文 | 30102篇 |
免费 | 4180篇 |
国内免费 | 2090篇 |
专业分类
化学 | 5084篇 |
晶体学 | 105篇 |
力学 | 5118篇 |
综合类 | 507篇 |
数学 | 12598篇 |
物理学 | 12960篇 |
出版年
2024年 | 65篇 |
2023年 | 280篇 |
2022年 | 686篇 |
2021年 | 809篇 |
2020年 | 968篇 |
2019年 | 880篇 |
2018年 | 822篇 |
2017年 | 1093篇 |
2016年 | 1269篇 |
2015年 | 938篇 |
2014年 | 1616篇 |
2013年 | 2421篇 |
2012年 | 1689篇 |
2011年 | 1959篇 |
2010年 | 1711篇 |
2009年 | 2049篇 |
2008年 | 1922篇 |
2007年 | 1879篇 |
2006年 | 1590篇 |
2005年 | 1401篇 |
2004年 | 1283篇 |
2003年 | 1090篇 |
2002年 | 1065篇 |
2001年 | 863篇 |
2000年 | 813篇 |
1999年 | 706篇 |
1998年 | 640篇 |
1997年 | 482篇 |
1996年 | 406篇 |
1995年 | 380篇 |
1994年 | 358篇 |
1993年 | 300篇 |
1992年 | 270篇 |
1991年 | 206篇 |
1990年 | 177篇 |
1989年 | 138篇 |
1988年 | 131篇 |
1987年 | 139篇 |
1986年 | 119篇 |
1985年 | 142篇 |
1984年 | 142篇 |
1983年 | 75篇 |
1982年 | 100篇 |
1981年 | 66篇 |
1980年 | 37篇 |
1979年 | 42篇 |
1978年 | 31篇 |
1977年 | 32篇 |
1976年 | 16篇 |
1973年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Numerical schemes for systems with multiple spatio-temporal scales are investigated. The multiscale schemes use asymptotic results for this type of systems which guarantee the existence of an effective dynamics for some suitably defined modes varying slowly on the largest scales. The multiscale schemes are analyzed in general, then illustrated on a specific example of a moderately large deterministic system displaying chaotic behavior due to Lorenz. Issues like consistency, accuracy, and efficiency are discussed in detail. The role of possible hidden slow variables as well as additional effects arising on the diffusive time-scale are also investigated. As a byproduct we obtain a rather complete characterization of the effective dynamics in Lorenz model. 相似文献
172.
It is shown that data on the dissociation rate of deuterium obtained in an experiment at the Sudbury Neutrino Observatory provides evidence that the Continuous Spontaneous Localization wavefunction collapse model should have mass–proportional coupling to be viable. 相似文献
173.
Using two different types of the laddering equations realized simultaneously by the associated Gegenbauer functions, we show that all quantum states corresponding to the motion of a free particle on AdS
2 and S
2 are splitted into infinite direct sums of infinite-and finite-dimensional Hilbert subspaces which represent Lie algebras u(1, 1) and u(2) with infinite- and finite-fold degeneracies, respectively. In addition, it is shown that the representation bases of Lie algebras with rank 1, i.e., gl(2, C), realize the representation of nonunitary parasupersymmetry algebra of arbitrary order. The realization of the representation of parasupersymmetry algebra by the Hilbert subspaces which describe the motion of a free particle on AdS
2 and S
2 with the dynamical symmetry groups U(1, 1) and U(2) are concluded as well. 相似文献
174.
A. M. Povolotsky V. B. Priezzhev Chin-Kun Hu 《Journal of statistical physics》2003,111(5-6):1149-1182
An asymmetric stochastic process describing the avalanche dynamics on a ring is proposed. A general kinetic equation which incorporates the exclusion and avalanche processes is considered. The Bethe ansatz method is used to calculate the generating function for the total distance covered by all particles. It gives the average velocity of particles which exhibits a phase transition from an intermittent to continuous flow. We calculated also higher cumulants and the large deviation function for the particle flow. The latter has the universal form obtained earlier for the asymmetric exclusion process and conjectured to be common for all models of the Kardar–Parisi–Zhang universality class. 相似文献
175.
利用拉曼型的Jaynes-Cummings模型传送两比特的未知原子态 总被引:6,自引:3,他引:3
实现量子态的隐形传送、尤其是多比特量子态的隐形传送在量子信息领域中有非常重要的作用,提出了一种隐形传送两比特未知原子态的方案,在此方案中,用两个两粒子纠缠态代替一个三粒子纠缠态作为量子信道,而且此方案可推广到隐形传送N比特的未知原子态。 相似文献
176.
Nonlinear susceptibility of a quantum dot (QD) embedded in a two-sided cavity, is studied theoretically from a weak-coupling to a strong-coupling regime. In the relevance of a quantum logic gate, the corresponding nonlinear phase shifts (Kerr effect) are estimated for coherent wavepackets including one photon on average. In the weak-coupling regime, the phase shift enhances strongly as a function of a coupling constant between the cavity photon and QD, and eventually saturates in the strong-coupling regime. We also show transmission spectra to evaluate the efficiency of the phase shift. Although the efficiency decreases monotonically in the weak-coupling regime, it rises in the strong-coupling regime. 相似文献
177.
178.
179.
Frequency dependence of ac conductivity from 1 to 105 Hz and time series of the conductivity at 2 kHz were measured along c-axis of thulium nitrate crystal, Tm(NO3)36H2O at temperatures from 203.15 to 293.15 K. The meta-stability was observed. The frequency spectra of the conductivity were similar to those in disorder system. Aging effect was observed. Non-periodic instability (burst) was found. Non-linear dynamical property was characterized by 1/f noise spectrum, limit cycle in return map and dependence of correlation exponent on embedding dimension. 相似文献
180.