全文获取类型
收费全文 | 10300篇 |
免费 | 2513篇 |
国内免费 | 786篇 |
专业分类
化学 | 633篇 |
晶体学 | 120篇 |
力学 | 1780篇 |
综合类 | 61篇 |
数学 | 458篇 |
物理学 | 6521篇 |
无线电 | 4026篇 |
出版年
2024年 | 40篇 |
2023年 | 103篇 |
2022年 | 183篇 |
2021年 | 191篇 |
2020年 | 262篇 |
2019年 | 239篇 |
2018年 | 233篇 |
2017年 | 269篇 |
2016年 | 329篇 |
2015年 | 353篇 |
2014年 | 635篇 |
2013年 | 623篇 |
2012年 | 620篇 |
2011年 | 847篇 |
2010年 | 637篇 |
2009年 | 709篇 |
2008年 | 756篇 |
2007年 | 756篇 |
2006年 | 730篇 |
2005年 | 620篇 |
2004年 | 572篇 |
2003年 | 516篇 |
2002年 | 477篇 |
2001年 | 457篇 |
2000年 | 394篇 |
1999年 | 321篇 |
1998年 | 286篇 |
1997年 | 269篇 |
1996年 | 221篇 |
1995年 | 185篇 |
1994年 | 172篇 |
1993年 | 136篇 |
1992年 | 108篇 |
1991年 | 80篇 |
1990年 | 80篇 |
1989年 | 47篇 |
1988年 | 33篇 |
1987年 | 23篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
对梁受正弦分布压力作用的情况,本文以矩形截面简支梁为例,通过构造满足所有边界条件和双调和方程的应力函数给出了相应的解析解,这为求解梁受任意分布压力作用的解的问题打下了基础。 相似文献
993.
994.
R. V. Palvelev 《Theoretical and Mathematical Physics》2008,156(1):1028-1040
We study the scattering of vortices in the Abelian (2+1)-dimensional Higgs model. We show that in the case of the symmetric head-on collision of N vortices, their trajectories are
rotated by the angle π/N after the collision.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 1, pp. 77–91, July, 2008. 相似文献
995.
G. Zanelato Yu. A. Pusep J. C. Galzerani D. I. Lubyshev P. P. Gonzlez-Borrero 《Physica E: Low-dimensional Systems and Nanostructures》2001,10(4)
The Raman spectra of the optical confined phonons in the GaAs/AlAs ultra-thin layer superlattices grown with different growth conditions were used to determine the compositional profiles and to study the process of segregation at the heterointerfaces. A modified kinetic model was developed in order to calculate the compositional profiles in the samples under investigation. The comparison between the experimentally obtained compositional profiles and those calculated by the kinetic model allowed us to determine the parameters characterizing the segregation. It was shown that the increase of pressure of As acts equivalently to the decrease of the growth temperature, resulting in a more abrupt compositional profile. 相似文献
996.
介绍了新研制的PC微机为控制机的电子束图形数字控制器的接口、结构、基本功能以及设计中应注意的主要环节。 相似文献
997.
We investigate the confinement properties of bounded, nonnegative, compactly supported vortices of axisymmetric incompressible Euler flows without swirl. We show that along one direction of the symmetry axis, its support can grow no faster than O[(t log t)1/2]. The rate at which it approaches the symmetry axis is also estimated. Together with the result of Maffei–Marchioro on the radial growth rate of the support, it is contained in a slowly expanding tubular region. The techniques of the above‐mentioned authors, Iftimie–Lopes–Nussenzveig and Iftimie–Sideris–Gamblin, are used. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
998.
One of the most well-known situations in which nonlinear effects must be taken into account to obtain realistic results is
the rotating beam problem. This problem has been extensively studied in the literature and has even become a benchmark problem
for the validation of nonlinear formulations. Among other approaches, the substructuring technique was proven to be a valid
strategy to account for this problem. Later, the similarities between the absolute nodal coordinate formulation and the substructuring
technique were demonstrated. At the same time, it was found the existence of a critical angular velocity, beyond which the
system becomes unstable that was dependent on the number of substructures. Since the dependence of the critical velocity was
not so far clear, this paper tries to shed some light on it. Moreover, previous studies were focused on a constant angular
velocity analysis where the effects of Coriolis forces were neglected. In this paper, the influence of the Coriolis force
term is not neglected. The influence of the reference conditions of the element frame are also investigated in this paper. 相似文献
999.
Richard Nader Michel Kazan Elie Moussaed Thomas Stauden Merten Niebelschütz Pierre Masri Jörg Pezoldt 《Surface and interface analysis : SIA》2008,40(9):1310-1317
The influence of Ge deposition prior to carbon interaction with 3° off‐axis Si(111) substrates on the structural and morphological properties of the formed silicon carbide (SiC) layer is studied. In situ reflection high‐energy electron diffraction (RHEED) and X‐ray diffraction (XRD) revealed the formation of the cubic silicon carbide (3C‐SiC) modification. In situ spectroscopic ellipsometry measurements revealed a decreasing 3C‐SiC thickness with increasing Ge predeposition. Atomic force microscopy (AFM) studies revealed that the surface overlayer morphology is mainly formed by periodic step arrangements whose relevant geometric parameters, i.e. lateral separation, height and terrace width, depend on the Ge content. Besides the changes of the step morphology, the surface roughness and the grain size and the strain of the formed 3C‐SiC decreases with increasing germanium precoverage. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
1000.