全文获取类型
收费全文 | 61207篇 |
免费 | 1864篇 |
国内免费 | 165篇 |
专业分类
化学 | 37846篇 |
晶体学 | 379篇 |
力学 | 1003篇 |
综合类 | 5篇 |
数学 | 11220篇 |
物理学 | 12783篇 |
出版年
2023年 | 394篇 |
2022年 | 605篇 |
2021年 | 826篇 |
2020年 | 886篇 |
2019年 | 912篇 |
2018年 | 1140篇 |
2017年 | 1077篇 |
2016年 | 2048篇 |
2015年 | 1712篇 |
2014年 | 1741篇 |
2013年 | 3778篇 |
2012年 | 3663篇 |
2011年 | 3672篇 |
2010年 | 2453篇 |
2009年 | 2188篇 |
2008年 | 3234篇 |
2007年 | 3042篇 |
2006年 | 2741篇 |
2005年 | 2678篇 |
2004年 | 2260篇 |
2003年 | 1920篇 |
2002年 | 1657篇 |
2001年 | 1283篇 |
2000年 | 1231篇 |
1999年 | 890篇 |
1998年 | 698篇 |
1997年 | 642篇 |
1996年 | 808篇 |
1995年 | 579篇 |
1994年 | 658篇 |
1993年 | 610篇 |
1992年 | 620篇 |
1991年 | 526篇 |
1990年 | 566篇 |
1989年 | 462篇 |
1988年 | 456篇 |
1987年 | 442篇 |
1986年 | 413篇 |
1985年 | 547篇 |
1984年 | 526篇 |
1983年 | 405篇 |
1982年 | 407篇 |
1981年 | 414篇 |
1980年 | 364篇 |
1979年 | 334篇 |
1978年 | 315篇 |
1977年 | 315篇 |
1976年 | 324篇 |
1974年 | 284篇 |
1973年 | 305篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
No analytic solutions of the Schrödinger equation are known for the quartic anharmonic oscillator. We show in this paper that there are closely related modified quartic oscillators with the potential depending on |x| for which analytic solutions for some states exist. These results can be extended to the higher order oscillators 相似文献
103.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions.
In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation
solutions.
Accepted 27 February 1996 相似文献
104.
A. Sánchez-Lavega A. Salazar A. Ocariz L. Pottier E. Gomez L.M. Villar E. Macho 《Applied Physics A: Materials Science & Processing》1997,65(1):15-22
Received: 16 September 1996/Accepted: 6 January 1997 相似文献
105.
106.
Some of the motivations for as well as the main points of the quantization of the Nappi-Witten string in the light-cone gauge are reviewed. 相似文献
107.
V.I. Fernández A. Iucci C.M. Naón 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):53-56
We present an extension of the Tomonaga-Luttinger model in which left and right-moving particles have different Fermi velocities.
We derive expressions for one-particle Green's functions, momentum-distributions, density of states, charge compressibility
and conductivity as functions of both the velocity difference ε and the strength of the interaction β. This allows us to identify
a novel restricted region in the parameter space in which the system keeps the main features of a Luttinger liquid but with
an unusual behavior of the density of states and the static charge compressibility κ. In particular κ diverges on the boundary
of the restricted region, indicating the occurrence of a phase transition.
Received 20 May 2002 / Received in final form 23 August 2002 Published online 19 November 2002 相似文献
108.
109.
Ricardo García-Pelayo Iván Salazar William C. Schieve 《Journal of statistical physics》1993,72(1-2):167-187
An analytically solvable model for sand avalanches of noninteracting grains of sand, based on the Chapman-Kolmogorov equations, is presented. For a single avalanche, distributions of lifetimes, sizes of overflows and avalanches, and correlation functions are calculated. Some of these are exponentials, some are power laws. Spatially homogeneous distributions of avalanches are also studied. Computer simulations of avalanches of interacting grains of sand are compared to the solutions to the Chapman-Kolmogorov equations. We find that within the range of parameters explored in the simulation, the approximation of noninteracting grains of sand is a good one. 相似文献
110.
We describe a general method that enables us to obtain all the singular terms of helicity amplitudes of n-parton processes at one loop. The algorithm uses helicity amplitudes at tree level and simple color algebra. We illustrate the method by calculating the singular part of the one-loop helicity amplitudes of all 2 → 3 parton subprocesses. The results are used to derive the soft gluon limit of the cross sections of all 2 → 4 parton scattering subprocesses which provide a useful initial condition for the angular ordering approximation to coherent multiple soft gluon emission, incorporated in existing Monte Carlo simulation programs. 相似文献