全文获取类型
收费全文 | 1828篇 |
免费 | 148篇 |
国内免费 | 58篇 |
专业分类
化学 | 198篇 |
晶体学 | 7篇 |
力学 | 920篇 |
综合类 | 22篇 |
数学 | 506篇 |
物理学 | 381篇 |
出版年
2024年 | 5篇 |
2023年 | 15篇 |
2022年 | 27篇 |
2021年 | 33篇 |
2020年 | 36篇 |
2019年 | 33篇 |
2018年 | 40篇 |
2017年 | 45篇 |
2016年 | 77篇 |
2015年 | 59篇 |
2014年 | 89篇 |
2013年 | 164篇 |
2012年 | 67篇 |
2011年 | 73篇 |
2010年 | 70篇 |
2009年 | 88篇 |
2008年 | 87篇 |
2007年 | 92篇 |
2006年 | 105篇 |
2005年 | 85篇 |
2004年 | 94篇 |
2003年 | 62篇 |
2002年 | 67篇 |
2001年 | 74篇 |
2000年 | 51篇 |
1999年 | 81篇 |
1998年 | 46篇 |
1997年 | 60篇 |
1996年 | 36篇 |
1995年 | 25篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有2034条查询结果,搜索用时 203 毫秒
101.
102.
103.
V. I. Fabrikant 《Archive of Applied Mechanics (Ingenieur Archiv)》2001,71(6-7):371-388
Summary The following mixed boundary-value problem for a transversely isotropic elastic half-space is considered. Arbitrary tangential
displacements are prescribed at the exterior of a circle, while the interior of the circle is free of tangential stress, and
the normal stress vanishes all over the boundary. The governing integral equation is solved exactly, in closed form, and in
terms of elementary functions. The method of continuation of solutions previously published by the author has been used here.
Several examples are considered. No similar results has been reported before, even in the case of an isotropic body.
Received 8 May 2000; accepted for publication 20 July 2000 相似文献
104.
The theory of fluid surfaces with elastic resistance to bending is applied to coexistent phase equilibria in biomembranes
composed of lipid bilayers. A simplified version of the model is used to simulate the necking and budding of closed vesicles.
相似文献
105.
C. Barentin P. Muller C. Ybert J.-F. Joanny J.-M. di Meglio 《The European physical journal. E, Soft matter》2000,2(2):153-159
The surface shear viscosity of monolayers formed at the surface of water by adsorbed polyethyl- eneoxyde and by stearic acid
is measured as a function of the surface pressure of the monolayer using a new surface viscometer. The principle of the viscometer
is the measurement of the drag force on a circular disk undergoing a uniform translation at the water surface: a hydrodynamic
model based on the lubrication approximation allows a calculation of the surface viscosities from the absolute measurement
of the drag forces.
Received: 26 August 1999 相似文献
106.
Ship-radiated noise is one of the important signal types under the complex ocean background, which can well reflect physical properties of ships. As one of the valid measures to characterize the complexity of ship-radiated noise, permutation entropy (PE) has the advantages of high efficiency and simple calculation. However, PE has the problems of missing amplitude information and single scale. To address the two drawbacks, refined composite multi-scale reverse weighted PE (RCMRWPE), as a novel measurement technology of describing the signal complexity, is put forward based on refined composite multi-scale processing (RCMP) and reverse weighted PE (RWPE). RCMP is an improved method of coarse-graining, which not only solves the problem of single scale, but also improves the stability of traditional coarse-graining; RWPE has been proposed more recently, and has better inter-class separability and robustness performance to noise than PE, weighted PE (WPE), and reverse PE (RPE). Additionally, a feature extraction scheme of ship-radiated noise is proposed based on RCMRWPE, furthermore, RCMRWPE is combined with discriminant analysis classifier (DAC) to form a new classification method. After that, a large number of comparative experiments of feature extraction schemes and classification methods with two artificial random signals and six ship-radiated noise are carried out, which show that the proposed feature extraction scheme has better performance in distinguishing ability and stability than the other three similar feature extraction schemes based on multi-scale PE (MPE), multi-scale WPE (MWPE), and multi-scale RPE (MRPE), and the proposed classification method also has the highest recognition rate. 相似文献
107.
《Journal of computational chemistry》2017,38(5):257-264
Two alternative approaches for the quantum‐mechanical calculation of the nuclear‐relaxation term of elastic and piezoelectric tensors of crystalline materials are illustrated and their computational aspects discussed: (i) a numerical approach based on the geometry optimization of atomic positions at strained lattice configurations and (ii) a quasi‐analytical approach based on the evaluation of the force‐ and displacement‐response internal‐strain tensors as combined with the interatomic force‐constant matrix. The two schemes are compared both as regards their computational accuracy and performance. The latter approach, not being affected by the many numerical parameters and procedures of a typical quasi‐Newton geometry optimizer, constitutes a more reliable and robust mean to the evaluation of such properties, at a reduced computational cost for most crystalline systems. © 2016 Wiley Periodicals, Inc. 相似文献
108.
This paper reports on geometry dependent viscosity curves of the biaxial thermotropic LC-Polymer Vectra B 950 measured with rectangular slit dies. The geometry dependence of the flow behaviour originates from the flow of two layers. The layer near the wall is highly flow oriented and free from defects. The layer in the bulk has an ordered texture. The thickness of the wall layer decreases with wall shear stress. Based on the Frank theory and the assumption that the core of a moving disclination is the smallest radius of distortion, the wall layer thickness is predicted and compared with experimental data. 相似文献
109.
110.
S. V. Matnyak 《International Applied Mechanics》2003,39(3):318-323
An asymmetric quasistationary problem for a prestressed half-plane with harmonic and Bartenev–Khazanovich potentials is solved based of the linearized theory of elasticity. The Mehler–Fock integral transform is used to solve the differential equations that describe the stress–strain state of the half-plane. The dependences of the normal and tangential stresses and stress intensity factors on the elongation are plotted 相似文献