全文获取类型
收费全文 | 11439篇 |
免费 | 1014篇 |
国内免费 | 807篇 |
专业分类
化学 | 7757篇 |
晶体学 | 65篇 |
力学 | 900篇 |
综合类 | 70篇 |
数学 | 818篇 |
物理学 | 3650篇 |
出版年
2024年 | 20篇 |
2023年 | 104篇 |
2022年 | 267篇 |
2021年 | 246篇 |
2020年 | 341篇 |
2019年 | 284篇 |
2018年 | 313篇 |
2017年 | 360篇 |
2016年 | 427篇 |
2015年 | 399篇 |
2014年 | 473篇 |
2013年 | 768篇 |
2012年 | 761篇 |
2011年 | 663篇 |
2010年 | 555篇 |
2009年 | 559篇 |
2008年 | 554篇 |
2007年 | 618篇 |
2006年 | 580篇 |
2005年 | 445篇 |
2004年 | 442篇 |
2003年 | 406篇 |
2002年 | 384篇 |
2001年 | 285篇 |
2000年 | 348篇 |
1999年 | 339篇 |
1998年 | 300篇 |
1997年 | 298篇 |
1996年 | 223篇 |
1995年 | 231篇 |
1994年 | 174篇 |
1993年 | 135篇 |
1992年 | 144篇 |
1991年 | 114篇 |
1990年 | 121篇 |
1989年 | 102篇 |
1988年 | 98篇 |
1987年 | 70篇 |
1986年 | 53篇 |
1985年 | 43篇 |
1984年 | 54篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 20篇 |
1980年 | 21篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Tungsten trioxide and titanium dioxide thin films were synthesised by pulsed laser deposition. We used for irradiations of oxide targets an UV KrF* (λ = 248 nm, τFWHM ≅ 20 ns, ν = 2 Hz) excimer laser source, at 2 J/cm2 incident fluence value. The experiments were performed in low oxygen pressure. The (0 0 1) SiO2 substrates were heated during the thin film deposition process at temperature values within the 300-500 °C range. The structure and crystalline status of the obtained oxide thin films were investigated by high resolution transmission electron microscopy. Our analyses show that the films are composed by nanoparticles with average diameters from a few to a few tens of nm. Moreover, the films deposited at substrate temperatures higher than 300 °C are crystalline. The tungsten trioxide films consist of a mixture of triclinic and monoclinic phases, while the titanium dioxide films structure corresponds to the tetragonal anatase phase. The oxide films average transmittance in the visible-infrared spectral range is higher than 80%, which makes them suitable for sensor applications. 相似文献
43.
We consider the two-dimensional one-component plasma without a background and confined to a half-plane near a metal wall. The particles are also subjected to an external potential acting perpendicular to the wall with an inverse-power-law Boltzmann factor. The model has a known solvable isotherm which exhibits a Kosterlitz-Thouless-type transition from a conductive to an insulator phase as the power law is varied. This allows predictions of theoretical methods of analyzing the Kosterlitz-Thouless transition to be compared with the exact solution. In particular, we calculate the asymptotic density profile by resumming its low-fugacity expansion near the zero-density critical coupling in the insulator phase, and solving a mean-field equation deduced from the first BGY equation. Agreement with the exact solution is obtained. As the former calculation makes essential use of the nested dipole hypothesis of Kosterlitz and Thouless, the validity of this hypothesis is explicitly verified. 相似文献
44.
We investigate the topology of the phase diagram of binary alloys on the fee lattice with first-neighbor antiferromagnetic interactions around the superdegenerate point, where the L10 and L12 phases meet. We treat the system as a hard-constraint lattice gas, following a procedure previously described by Lebowitzet al. We perform cluster variation method calculations in theT0 limit and Monte Carlo simulations directly atT=0 K on the ground states of the superdegenerate point. We find that: (i) there is no disordered phase in the neighborhood of this point; (ii) a phase L for which two of the four cubic sublattices have the same average occupancy and each of the two others are different appears between L10 and L12; (iii) the transition L/L12 is of first order. 相似文献
45.
We consider the equilibrium dynamics of a system consisting of a spin interacting with an ideal Fermi gas on the lattice , 3. We present two examples: when this system is unitarily equivalent to an ideal Fermi gas or to a spin in an ideal Fermi gas without interaction between them. 相似文献
46.
A low-temperature expansion for the free energy density of lattice animals is derived. Analysis of the series yields a collapse transition temperature ofT
c - 0.54, in close agreement with previous estimates. It is demonstrated that
p,k, the number ofp-particle,p-bond animals, obeys the asymptotic scaling law log
p,k
pg(k/p) + o(p). The low-temperature series and numerical data are used to estimate the scaling function. 相似文献
47.
Boguslaw Zegarliński 《Journal of statistical physics》1986,43(3-4):687-705
We give a condition on a Gibbs measure for an attractive Markov specification, which assures extremality and the global Markov property. As an example of application we consider the class of attractive Markov specifications defined on a compact configuration space over a two-dimensional lattice by the interaction Hamiltonians (assumed to have a finite set of periodic ground configurations) satisfying Peierl's condition. We prove that each extremal Gibbs measure for such a specification, at sufficiently low temperature, has the global Markov property.On leave of absence from the Institute of Theoretical Physics, University of Wrocaw, Poland. 相似文献
48.
A heated injection system for a microprocessor-controlled GC has been developed for the (GC)2 analysis of the volatile phase of whole smoke of a cigarette. Effects of injection port temperature and the presence of a Cambridge filter pad are demonstrated. Chromatograms are shown for smoke samples with and without a Cambridge Filter with the sample valve oven at 25°, 165° and 205°C. The use of a flame ionization and a nitrogen-phosphorous detector is illustrated. 相似文献
49.
50.
In this paper we discuss the existence of generic long-range correlations in spatially homogeneous and stable equilibrium states of closed lattice gas automata whose stochastic collision rules violate the symmetry conditions of detailed balance and in addition satisfy local conservation laws. Such correlations occur even though the collision rules are strictly local and invariant under all symmetries of the lattice. First a phenomenological (Langevin equation) approach is discussed. Next we present a theoretical analysis on the basis of an approximate microscopic (ring kinetic) theory. This theory is used to calculate the amplitude ofr
– tails in the spatial correlations, and the result is compared with computer simulations. 相似文献