全文获取类型
收费全文 | 322篇 |
免费 | 30篇 |
国内免费 | 5篇 |
专业分类
化学 | 8篇 |
晶体学 | 1篇 |
力学 | 131篇 |
综合类 | 1篇 |
数学 | 48篇 |
物理学 | 168篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 14篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 34篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1977年 | 1篇 |
排序方式: 共有357条查询结果,搜索用时 390 毫秒
91.
Based on [1], the stress structures of the smooth region and shear lip of the specimens have been investigated in the paper.
The characteristics of the stress structure in the smooth region have been found that the variable z can separated out; the
stresses in the midsection can be obtained by the plane strain FEM results or HRR structure modified by the stress triaxiality.
The effects of load level and thickness on the stress structure can be reflected by the distribution of CTOD along the thickness
direction. The obtained expressions of the stresses are very simple and visualized. The analyses of the stress structure in
the shear lip show that the stresses can be obtained by different methods of interpolation to a certain precise degree.
A new degree parameter of the plane strain state has been put forward and studied. The parameter can reflect relatively well
the variation of the kind and thickness of the specimen as well as the load level. The fracture parameter has also been investigated
to be sure that it can be obtained by modified CTOD with the stress triaxiality. 相似文献
92.
无叶扩压器离心式压气机内旋涡运动的数值研究 总被引:1,自引:0,他引:1
本文的目的是用数值计算方法来研究离心式压气机叶轮内的旋涡运动。所用的数值方法是在工程热物理所发展的时间相关有限体积法.在流场计算的基础上,应用速度矢量、微团的面积和体积示踪、旋度和熵增等后处理程序与方法来研究与显示旋涡运动的存在与发展.文中用这些手段研究了离心式叶轮中的各类旋涡并给出了拓扑图,对于二次流动还给出了它的模型. 相似文献
93.
94.
Paramasivam Senthilkumaran Frank Wyrowski Hagen Schimmel 《Optics and Lasers in Engineering》2005,43(1):43-56
Optical vortex stagnation problem in Iterative Fourier Transform Algorithm occurs due to the termination of the process of self annihilation of optical vortices. The role played by propagation and inverse propagation operators combined with the Fourier domain constraint in this vortex annihilation process in the initial stage of the iterative procedure is studied. The understanding of this process recommends the process of forced annihilation as a solution to this stagnation problem and is demonstrated in this paper. 相似文献
95.
New development constraints prompted by new pollutant emissions and fuel consumption standards (Corporate Average Economy Fuel) require that automobile manufacturers develop new flow control devices capable of reducing the aerodynamic drag of motor vehicles. The solutions envisaged must have a negligible impact on the vehicle geometry. In this context, flow control by continuous suction is seen as a promising alternative. The control configurations identified during a previous 2D numerical analysis are adapted for this purpose and are tested on a 3D geometry. A local suction system located on the upper part of the rear window is capable of eliminating the rear window separation on simplified fastback car geometry. Aerodynamic drag reductions close to 17% have been obtained. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
96.
97.
S. E. Korshunov 《Journal of statistical physics》1986,43(1-2):17-32
For two-dimensional uniformly frustratedXY models the group of symmetry spontaneously broken in the ground state is a cross product of the group of two-dimensional rotations by some discrete group of finite order. Different possibilities of phase transitions in such systems are investigated. The transition to the Coulomb gas with noninteger charges is widely used when analyzing the properties of relevant topological excitations. The number of these excitations includes not only domain walls and traditional (integer) vortices, but also vortices with a fractional number of circulation quanta which are to be localized at bends and intersections of domain walls. The types of possible phase transitions prove to be dependent on their relative sequence: in the case the vanishing of domain wall free energy occurs earlier (at increasing temperature) than the dissociation of pairs of ordinary vortices, the second phase transition is to be associated with dissociation of pairs of fractional vortices. The general statements are illustrated with a number of examples. 相似文献
98.
S. De Nicola R. Fedele D. Jovanovic B. Malomed M. A. Man'ko V. I. Man'ko P. K. Shukla 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,54(1):113-119
We present one-dimensional (1D) stability analysis of a recently
proposed method to filter and control localized states of the
Bose–Einstein condensate (BEC), based on novel trapping
techniques that allow one to conceive methods to select a
particular BEC shape by controlling and manipulating the external
potential well in the three-dimensional (3D)
Gross–Pitaevskii equation (GPE). Within the framework of this
method, under suitable conditions, the GPE can be exactly
decomposed into a pair of coupled equations: a transverse
two-dimensional (2D) linear Schr?dinger equation and a
one-dimensional (1D) longitudinal nonlinear Schr?dinger
equation (NLSE) with, in a general case, a time-dependent
nonlinear coupling coefficient. We review the general idea how
to filter and control localized solutions of the GPE. Then,
the 1D longitudinal NLSE is numerically solved
with suitable non-ideal controlling potentials that differ from
the ideal one so as to introduce relatively small errors
in the designed spatial profile. It is shown that a BEC with an
asymmetric initial position in the confining potential exhibits
breather-like oscillations in the longitudinal direction but,
nevertheless, the BEC state remains confined within the potential
well for a long time. In particular, while the condensate remains
essentially stable, preserving its longitudinal soliton-like
shape, only a small part is lost into “radiation”. 相似文献
99.
Vortices in the N-gap (N ≥ 1) superconductor is studied by Dirac δ function. The topological structure of vortices can be characterized by Brouwer degree and Hopf index, i.e. (βtη1,… , βNηN ). The magnetic flux and circulation of vortices without London approximation in the N-gap superconductor are calculated. The universal modified London equation is given for the case that each individual condensate is conserved or not conserved. 相似文献
100.
热波传热机制是超流氦传热非常重要的一个方面.在小热流密度的情况下,超流氦中的热波完全保持加热热流的波形,热量的传输完全靠热波来完成;随着热流密度的增加到一定程度,会在超流氦浴中激发量子涡旋.量子涡旋使热波发展成为热激波.在开放氦浴中,热波的波形不同于狭窄通道里的热波,在热波的尾部会出现一个冷却波;并且随着加热时间的变化,冷却波的形状和幅度会发生很大的变化.运用二流体模型和涡旋方程对超流氦中的热波进行了计算,实验结果与计算结果吻合得较好.
关键词:
超流氦
热波
量子涡旋
热激波 相似文献