全文获取类型
收费全文 | 375篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学 | 193篇 |
晶体学 | 9篇 |
力学 | 7篇 |
数学 | 31篇 |
物理学 | 141篇 |
出版年
2022年 | 3篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2014年 | 2篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 23篇 |
2007年 | 10篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 6篇 |
2003年 | 21篇 |
2002年 | 26篇 |
2001年 | 6篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有381条查询结果,搜索用时 343 毫秒
31.
A new and simple method to expand the anharmonic vibrational wave functions with respect to the harmonic oscillator wave functions is proposed. The coefficients of the expansion are given as matrix elements of the S function of the contact transformation in the perturbation theory and the explicit expressions of these coefficients are given within the approximation to the second order in λ. As an example of the expansion, the wave functions of water molecules were calculated and applied to the calculation of infrared band intensities and average values of dipole moments in several states. 相似文献
32.
33.
A simple anharmonic potential containing 18 quadratic, 6 cubic, and 6 quartic constants is proposed to fit 124 vibrational frequencies of 1,1-dichloroethylene and its 37Cl isotope in the region from 10 000 to 350 cm?1. The level patterns in the first and the second overtone regions of the CH2 stretching vibrations are explained by the absence of large higher-order interaction terms between the two CH stretching coordinates. 相似文献
34.
35.
Machida M 《Physical review letters》2003,90(3):037001
We numerically investigate Josephson vortex flow states in layered high-T(c) superconductors motivated by a recent experimental observation for accurate periodic magnetic field dependences of the Josephson vortex flow resistance over a wide range of magnetic field (0.5-4.0 T). We confirm in our mesoscale simulations that dynamical matching of Josephson vortex lattice with sample edge is responsible for the periodic dependence. The present simulations reveal that the Josephson vortex lattice flow speed is particularly suppressed when the moment of vortex entry matches that of vortex escape. Thus, the possible matching situations are taken into account and the observed periodicity is successfully explained. 相似文献
36.
Machida K Takehara E Kobayashi H Kikuchi M 《Chemical & pharmaceutical bulletin》2003,51(12):1417-1419
Two new iridoid glycosides, 7 beta,8 beta-epoxy-8 alpha-dihydrogeniposide (1) and 8-epiapodantheroside (2), were isolated, together with six known (3-8) and three artifact (9-11) iridoids, from the leaves of Gardenia jasminoides cv. fortuneana Hara. Their structures were established based on chemical and spectral data. 相似文献
37.
Machida S Mineta S Fujimori A Nakahara H 《Journal of colloid and interface science》2003,260(1):135-141
From AFM observation of transferred films on mica, it has been found that mixed monolayers of hexadecanol with poly(vinyl stearate) give a film with a less-defective and flat surface by spreading from bulk solids of those mixtures onto a water surface without using any organic solvent. As a result, those mixed monolayers have a considerably larger effect on retardation of water evaporation in comparison with those spread from the solution of the mixtures. After the saturated surface pressure of the mixed monolayer spread from the bulk solids, an enhanced effect on retardation of water evaporation was found, accompanied by the preferential spreading of hexadecanol and the gradual reduction of defects in the mixed monolayer. 相似文献
38.
We show that the Nomura algebra of the nonsymmetric Hadamard model coincides with the Bose–Mesner algebra of the directed Hadamard graph. 相似文献
39.
The uniqueness of a binary doubly-even self-dual [48, 24, 12] code is used to prove that a self-orthogonal 5-(48, 12, 8) design, as well as some of its derived and residual designs, including a quasi-symmetric 2-(45, 9, 8) design, are all unique up to isomorphism.Received November 5, 2003 相似文献
40.
In this paper, the experimental results of brittle-crack propagation and arrest on structural steels are analyzed using the finite-difference method. The test specimens used are double-tension and double-cantilever type (DCB). It is found that dynamic consideration is indispensable for general interpretation of fast fracture and crack arrest and material toughness can be defined as a function of temperature and crack velocity. Using the defined fracture toughness, crack-propagation-arrest behavior can be predicted by crack-propagation simulation if the condition of boundary loading of a specimen is known. This implies a possibility to develop simple methods for crack-arrester design. 相似文献