全文获取类型
收费全文 | 17915篇 |
免费 | 1604篇 |
国内免费 | 730篇 |
专业分类
化学 | 4777篇 |
晶体学 | 17篇 |
力学 | 1331篇 |
综合类 | 141篇 |
数学 | 9017篇 |
物理学 | 4966篇 |
出版年
2024年 | 27篇 |
2023年 | 183篇 |
2022年 | 273篇 |
2021年 | 383篇 |
2020年 | 440篇 |
2019年 | 468篇 |
2018年 | 348篇 |
2017年 | 398篇 |
2016年 | 625篇 |
2015年 | 500篇 |
2014年 | 799篇 |
2013年 | 1333篇 |
2012年 | 769篇 |
2011年 | 826篇 |
2010年 | 777篇 |
2009年 | 1021篇 |
2008年 | 1208篇 |
2007年 | 1251篇 |
2006年 | 1035篇 |
2005年 | 770篇 |
2004年 | 660篇 |
2003年 | 739篇 |
2002年 | 716篇 |
2001年 | 547篇 |
2000年 | 567篇 |
1999年 | 494篇 |
1998年 | 461篇 |
1997年 | 361篇 |
1996年 | 278篇 |
1995年 | 219篇 |
1994年 | 210篇 |
1993年 | 193篇 |
1992年 | 175篇 |
1991年 | 127篇 |
1990年 | 106篇 |
1989年 | 102篇 |
1988年 | 114篇 |
1987年 | 88篇 |
1986年 | 79篇 |
1985年 | 112篇 |
1984年 | 88篇 |
1983年 | 29篇 |
1982年 | 56篇 |
1981年 | 50篇 |
1980年 | 51篇 |
1979年 | 44篇 |
1978年 | 39篇 |
1977年 | 37篇 |
1976年 | 36篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
We study a discrete dynamical system whose evolution is governed by rules similar to those of Conway's game of Life but also include a stochastic element (parametrized by a temperature). Statistical properties that are examined are density as a function of temperature and entropy (suitably defined). A phase transition and a certain thermodynamic constant of the motion are observed.Lady Davis Visiting Scientist at the Technion 1974–75. 相似文献
202.
Wei-Shih Yang 《Journal of statistical physics》1987,49(1-2):1-32
The grand canonical ensemble of a two-dimensional Coulomb system with±1 charges is proved to have screening phenomena in its high-temperature region. The Coulomb potential in a finite region is assumed to be (–)–1, where
is the Laplacian with zero boundary conditions on. The hard-core condition is not assumed. The model is set up by separating (–)–1 into a shortrange part and a long-range part depending on a parameter. The self-energies are subtracted only for the short-range part and therefore a choice of is a choice of subtraction of self-energies. The method of proof is in general the same as that of Brydges-Federbush Debye screening, except that here a modification for the short-range part of the potentials is needed. 相似文献
203.
Using Gawedzki and Kupiainen's rigorous block spin transformation method, we study critical phenomena in 4 spin systems in four dimensions. In Part I of this work we investigate in detail the renormalization group trajectory of the system not exactly at the critical point. 相似文献
204.
Martin Macháček 《Journal of statistical physics》1987,47(5-6):949-952
We define mathematically a class of dynamical systems that exhibit relaxation corresponding to that observed in physical systems, and then show that this class is identical with the class ofK-mixing dynamical systems. 相似文献
205.
A one-dimensional system of hard-rod particles with rotational-like internal degrees of freedom is considered. Particles interact with each other through the infinite-range, infinitely weak attractive Kac potential, and through a nearest-neighbor short-range potential. The latter depends also on the internal states of the interacting particles. Exact results for thermodynamic properties and for some correlation functions are obtained. It is found that the considered system exhibits several first-order transitions between phases with different rotational structure, i.e., with different ordering with respect to the internal degrees of freedom. The calculated equation of state seems to suggest that in the solutions of liquid-crystalline substances in neutral solvents there may exist regions in which the coefficient of thermal expansion is negative—an effect similar to that well known in liquid water. 相似文献
206.
A. G. Schlijper 《Journal of statistical physics》1985,40(1-2):1-27
A new derivation is presented of some variational approximations for classical lattice systems that belong to the class of cluster-variation methods, among them the well-known Bethe-Peierls and Kramers-Wannier approximations. The limiting behavior of a hierarchical sequence of cluster-variation approximations, the so-calledC hierarchy, is discussed. It is shown that this hierarchy provides a monotonically decreasing sequence of upper boundsf
n on the free energy per lattice sitef and thatf
n f asn . Our results are based on extension theorems for states given on subsets of the lattice, which might be of some independent interest, and on an application of transfer matrix concepts to the variational characterization of translation-invariant equilibrium states. 相似文献
207.
Robert J. Deissler 《Journal of statistical physics》1985,40(3-4):371-395
The time-dependent generalized Ginzburg-Landau equation is an equation that is related to many physical systems. Solutions of this equation in the presence of low-level external noise are studied. Numerical solutions of this equation in thestationary frame of reference and with anonzero group velocity that is greater than a critical velocity exhibit a selective spatial amplification of noise resulting in spatially growing waves. These waves in turn result in the formation of a dynamic structure. It is found that themicroscopic noise plays an important role in themacroscopic dynamics of the system. For certain parameter values the system exhibits intermittent turbulent behavior in which the random nature of the external noise plays a crucial role. A mechanism which may be responsible for the intermittent turbulence occurring in some fluid systems is suggested. 相似文献
208.
E. M. Chudnovsky 《Journal of statistical physics》1985,41(5-6):877-897
It is shown that biological-natural-selection-like behavior can occur, as a general type of time evolution, in a statistical system where detailed balance is violated owing to the presence of metastable energy states. A model of a non-equilibrium phase transition corresponding to the spontaneous origin of self-reproduction in the system is suggested. After a phase transition, the system passes from one quasistationary distribution of self-reproducing subsystems to another, with an increase in the total organization, as long as the growth of the energy flow through the system or a reduction of energy dissipation in the system is possible. The entropy production is calculated for this process in terms of selective values of Eigen's theory for self-organization in autocatalytic systems. Correspondence of the extremal principle of Eigen's theory with the criterion of evolution in Prigogine's thermodynamics is established. 相似文献
209.
It is proposed in this paper to use the generalized cell mapping to locate strange attractors of dynamical systems and to determine their statistical properties. The cell-to-cell mapping method is based upon the idea of replacing the state space continuum by a large collection of state space cells and of expressing the evolution of the dynamical system in terms of a cell-to-cell mapping. This leads to a Markov chain which in turn allows us to compute all the statistical properties as well as the invariant distribution. After a general discussion, the method is applied in this paper to strange attractors of a variety of systems governed either by point mappings or by differential equations. The results indicate that it is a viable, effective and attractive method. Some comments on this method in comparison with the method of direct iteration will also be made. 相似文献
210.
A. Yu. Grosberg 《Journal of statistical physics》1985,38(1-2):149-160
The collapse (globulization) of an ideal heteropolymer chain under the action of an external attractive field is considered. The problem of the collapse of different types of primary structures, including mobile, periodic, large-block, and statistical structures, is formulated. It is shown that for a random heteropolymer, the mathematical image of the globular state is the chain-length independence of the probability distribution of a random thermal distribution function of the end monomer coordinates. The free energy per monomer of a chain in a globular state and local densities of monomers of all types are shown to be a self-averaging quantities. An exactly solvable model is proposed for a globule formed by a statistical heteropolymer chain. In this model, different types of monomers are attracted to different centers by linear elastic forces with identical elastic constants. The modulus of elasticity is obtained for a heteropolymer globule with respect to the attraction of different types of monomers in different directions. It is shown that this modulus is higher for a short-periodic polymer than for a statistical one. 相似文献