全文获取类型
收费全文 | 3579篇 |
免费 | 219篇 |
国内免费 | 223篇 |
专业分类
化学 | 1069篇 |
晶体学 | 10篇 |
力学 | 159篇 |
综合类 | 29篇 |
数学 | 1273篇 |
物理学 | 1481篇 |
出版年
2024年 | 6篇 |
2023年 | 49篇 |
2022年 | 48篇 |
2021年 | 58篇 |
2020年 | 80篇 |
2019年 | 77篇 |
2018年 | 59篇 |
2017年 | 78篇 |
2016年 | 74篇 |
2015年 | 84篇 |
2014年 | 123篇 |
2013年 | 203篇 |
2012年 | 114篇 |
2011年 | 147篇 |
2010年 | 119篇 |
2009年 | 231篇 |
2008年 | 238篇 |
2007年 | 308篇 |
2006年 | 271篇 |
2005年 | 178篇 |
2004年 | 204篇 |
2003年 | 190篇 |
2002年 | 165篇 |
2001年 | 141篇 |
2000年 | 115篇 |
1999年 | 109篇 |
1998年 | 99篇 |
1997年 | 114篇 |
1996年 | 83篇 |
1995年 | 55篇 |
1994年 | 31篇 |
1993年 | 21篇 |
1992年 | 23篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 19篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有4021条查询结果,搜索用时 15 毫秒
991.
The formation of the interface between C60 thin films and the Cu(110) surface has been investigated in situ using reflectance difference spectroscopy (RDS). The electronic interaction between C60 molecules in the first monolayer and the substrate inhibits low‐energy intramolecular transitions, whereas the C60 molecules above the first monolayer are effectively decoupled from the substrate. The morphology of C60 thin films prepared at room temperature is thermally stable up to 500 K. Above this threshold, optical spectroscopy and low energy electron diffraction (LEED) indicate the formation of rather large three dimensional C60 islands on a one monolayer thick wetting layer. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
992.
LIU Chun-Ping 《理论物理通讯》2005,43(1):13-16
By using the general solutions of a new coupled Riccati equations, a direct algebraic method is described to construct doubly periodic solutions (Jacobi elliptic function solution) for the coupled nonlinear Klein-Gordon equations.It is shown that more doubly periodic solutions and the corresponding solitary wave solutions and trigonometric function solutions can be obtained in a unified way by this method. 相似文献
993.
Antonio Luiz P.S. Campos Adaildo Gomes d'Assunção 《International Journal of Infrared and Millimeter Waves》2004,25(1):15-27
This work presents a sensitivity analysis for the resonant frequency and bandwidth of frequency selective surfaces (FSS) as a function of the structural parameters. The frequency selective surface structure considered here is composed by crossed dipole conductive patches deposited on an anisotropic dielectric layer. Firstly, the moment method is used in combination with the immittance technique in the spectral domain to determine the frequency response of the analyzed structure. Secondly, numerical techniques are used to obtain the resonant frequency and bandwidth sensitivities as a function of the considered FSS structural parameters. 相似文献
994.
Françoise Cornu Bernard Jancovici Lesser Blum 《Journal of statistical physics》1988,50(5-6):1221-1243
We revisit the equilibrium classical statistical mechanics of the two-dimensional one-component plasma, for the special value =2 of the coupling constant. Using a new method, we find that the model is solvable (then-body densities can be explicitly computed) for a larger class of inhomogeneous backgrounds. In particular, we can deal with a doubly periodic background; this is a classical model for a crystal made of fixed ions and mobile electrons. At =2, this system is conducting: the correlations have a fast decay, and the Stillinger-Lovett screening sum rule is obeyed. 相似文献
995.
J. K. Percus 《Journal of statistical physics》1993,71(5-6):1201-1211
We study idealized random sequential adsorption on a lattice, with adsorption probabilities inhomogeneous both in space and in time, and including the possibility of cooperativity. Attention is directed to the mean occupancy of a given site as a function of time, which is represented by a weighted random walk on the lattice. In the special case of nearest neighbor exclusion, the walk is transformed to one in which only neighbors of occupied sites can be occupied, but with a renormalized probability. Reduction theorems are presented, with which the general case of a tree lattice is completely solved in inverse form. 相似文献
996.
Pattrawin Gasemjit Diethelm Johannsmann 《Journal of polymer science. Part A, Polymer chemistry》2006,44(20):3031-3036
The flow behavior of the near-surface region of polystyrene films was studied via the decay kinetics of imprinted corrugation gratings at elevated temperatures. The speed of the decay is the result of a balance between surface tension, on the one hand, and viscous drag, on the other. Depth profiling is possible because the penetration depth of a surface wave is proportional to its wavelength. From the dependence of the decay rate on the penetration depth one concludes that the surface region displays an increased molecular mobility. The soft surface layer has a thickness of about 20 nm. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3031–3036, 2006 相似文献
997.
998.
We have investigated the influence of translational excitation on the reactivity of atomic fluorine with the Si(100) surface via molecular dynamics simulations using a first-principles-derived interaction potential. Surface reactivity is contrasted for both clean and partially fluorinated surfaces with the results of previous simulations of F2 molecules impinging on Si(100) surfaces, indicating many similarities between the dynamics of F atoms and F2 molecules. Mechanisms for the reaction are proposed based on reactivity trends and scattered product energy and angular distributions, including evidence for the existence of a precursor-mediated adsorption pathway for low incident energy F atoms on partially fluorinated surfaces. 相似文献
999.
1000.
本文得出一个一般形式的拓扑型的极大极小定理,它包含的主要结果为特例,而且回答了[3]中提出的一个未解决问题。 相似文献