全文获取类型
收费全文 | 328篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
化学 | 12篇 |
晶体学 | 3篇 |
力学 | 211篇 |
综合类 | 2篇 |
数学 | 48篇 |
物理学 | 74篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 11篇 |
2014年 | 12篇 |
2013年 | 17篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 15篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 12篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 8篇 |
2000年 | 15篇 |
1999年 | 8篇 |
1998年 | 14篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有350条查询结果,搜索用时 15 毫秒
41.
A numerical/analytical approach is proposed to determine the stress intensity factors KI, KII, and KIII of a 3D internal crack. The main point of this approach is the meshing technique that can model very sharp crack fronts. The meshing technique is based on an elliptical coordinate transformation that starts from a circular crack. It allows the obtainment of a curved crack front with elements normal to the crack front. Remarkable accuracy can be obtained for elliptical crack fronts with axes ratio smaller that 0.01. Accuracy demonstration is provided for cylindrical element with an inclined internal crack subjected to uni-axial tension. This case corresponds to crack propagation for all three modes of loading, the solution of which can checked with references’ results. 相似文献
42.
The fundamental solutions of elasticity are used to establish a numerical method for elastic and plastic multiple crack problems in two dimensions. The continuous distributions of the point forces, dislocations, and the plastic sources are used systematically to model the crack, non-crack boundary, and the plastic deformation. Use of these singularities are guided strictly by the physical interpretation of the problem. We adopt Muskhelishvili's complex variable formalism that facilitate the analytical evaluation of the integrals representing the continuous distributions of the singularities. The resulting numerical method is concise and accurate enough to be used for elastic and plastic multiple crack problems. 相似文献
43.
Yanmin Wang Eric Forssberg Peng Lin 《Particle & Particle Systems Characterization》2005,22(5):336-344
This paper presents the experimental results on the wet grinding of a moist calcium carbonate material in a hybrid comminution system, which consists of a high pressure roller mill (HPRM) and a subsequent stirred bead mill. The results show that the pre‐treatment of the material with the HPRM could result in energy saving and efficient size reduction during the subsequent wet ultra‐fine grinding in the stirred bead mill. It was found that the level of fineness of the ground product is dramatically influenced by the number of repeat passes of pre‐grinding in the HRPM. The formation of micro‐cracks in the particles under compressive loads was discussed in order to elucidate the role of the HRPM as a pre‐grinder in the hybrid comminution system. The simulated breakage behaviors of various irregular shaped particles indicate that the tortuous micro‐crack propagation paths and the crack branching behavior are related to the heterogeneity of the particle and the stress distributions. 相似文献
44.
Carole Fraschini Rodica Plesu Jose‐Ramon Sarasua Robert E. Prud'homme 《Journal of Polymer Science.Polymer Physics》2005,43(22):3308-3315
A polylactide of high optical purity was crystallized between 100 and 140 °C, in‐between two glass slides, and its morphology was investigated by polarizing optical microscopy, scanning electron microscopy, and atomic force microscopy, during subsequent heating and cooling cycles between ?15 °C and the crystallization temperature. It was found that dark circular rings show up on cooling on top of the spherulites and represent cracks of about 300 nm in width. This phenomenon is completely reversible, and the heating–cooling curves are centered at about 56 °C, which coincide with the Tg of polylactide. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3308–3315, 2005 相似文献
45.
On Some Nonclassical Problems of Fracture Mechanics Taking into Account the Stresses Along Cracks 总被引:1,自引:1,他引:0
A. N. Guz 《International Applied Mechanics》2004,40(8):937-941
The paper reports on the results from analysis of some nonclassical fracture problems that allow for stresses along cracks. The results have been obtained by the author and his collaborators at the Institute of Mechanics (Kiev) since 1980 相似文献
46.
The Self-Similar Crack Expansion (SSCE) method is used to calculate stress intensity factors for three-dimensional cracks in an infinite medium or semi-infinite medium by the boundary integral element technique, whereby, the stress intensity factors at crack tips are determined by calculating the crack-opening displacements over the crack surface. For elements on the crack surface, regular integrals and singular integrals are precisely evaluated based on closed form expressions, which improves the accuracy. Examples show that this method yields very accurate results for stress intensity factors of penny-shaped cracks and elliptical cracks in the full space, with errors of less than 1% as compared with analytical solutions. The stress intensity factors of subsurface cracks are in good agreement with other analytical solutions. 相似文献
47.
利用复变函数方法,通过构造保角映射,研究了一维六方准晶中带不对称三裂纹的圆形孔口的反平面剪切问题,给出了Ⅲ型裂纹问题的应力强度因子,在极限情形下,不仅可以还原为已有的结果,而且求得一维六方准晶中L裂纹问题在裂纹尖端的应力强度因子. 相似文献
48.
Transient response of two collinear dielectric cracks in a piezoelectric solid under inplane impacts
Fang Liu 《Applied mathematics and computation》2010,217(8):3779-3791
The paper is focused on the dynamic analysis of two collinear dielectric cracks in a piezoelectric material under the action of in-plane electromechanical impacts. Considering the dielectric permeability of crack interior, the electric displacements at the crack surfaces are governed by the jumps of electric potential and crack opening displacement across the cracks. The permeable and impermeable crack models are the limiting cases of the general one. The Laplace and Fourier transform techniques are further utilized to solve the mixed initial-boundary-value problem, and then to obtain the singular integral equations with Cauchy kernel, which are solved numerically. Dynamic intensity factors of stress, electric displacement and crack opening displacement are determined in time domain by means of a numerical inversion of the Laplace transform. Numerical results for PZT-5H are calculated to show the effects of the dielectric permeability inside the cracks, applied electric loadings and the geometry of the cracks on the fracture parameters in graphics. The observations reveal that based on the COD intensity factor, a positive electric field enhances the dynamic dielectric crack growth and a negative one impedes the dynamic dielectric crack growth in a piezoelectric solid. 相似文献
49.
In this paper, we deal with the acoustic inverse scattering problem for reconstructing cracks of possibly different types from the far‐field map. The scattering problem models the diffraction of waves by thin two‐sided cylindrical screens. The cracks are characterized by their shapes, the type of boundary conditions and the boundary coefficients (surface impedance). We give explicit formulas of the indicator function of the probe method, which can be used to reconstruct the shape of the cracks, distinguish their types of boundary conditions, the two faces of each of them and reconstruct the possible material coefficients on them by using the far‐field map. To test the validity of these formulas, we present some numerical implementations for a single crack, which show the efficiency of the proposed method for suitably distributed surface impedances. The difficulties for numerically recovering the properties of the crack in the concave side as well as near the tips are presented and some explanations are given. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
50.
The interaction of four parallel non-symmetric permeable cracks in a piezoelectric/piezomagnetic composite plane subjected to anti-plane shear stress loading was studied by the Schmidt method. The problem was formulated through a Fourier transform into four pairs of dual integral equations, in which unknown variables are jumps of displacements across the crack surfaces. To solve the dual integral equations, the jumps of displacements across the crack surfaces were directly expanded as a series of Jacobi polynomials. Finally, the relationships among the electric displacement, magnetic flux and stress fields near the crack tips were obtained. The results show that the stress, the electric displacement and the magnetic flux intensity factors at the crack tips depend on the lengths and spacing of cracks. It was also revealed that the crack shielding effect is present in piezoelectric/piezomagnetic composites. 相似文献