全文获取类型
收费全文 | 1034篇 |
免费 | 18篇 |
国内免费 | 5篇 |
专业分类
化学 | 548篇 |
晶体学 | 7篇 |
力学 | 24篇 |
数学 | 141篇 |
物理学 | 337篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 5篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 22篇 |
2017年 | 25篇 |
2016年 | 31篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 59篇 |
2012年 | 49篇 |
2011年 | 56篇 |
2010年 | 46篇 |
2009年 | 47篇 |
2008年 | 67篇 |
2007年 | 48篇 |
2006年 | 47篇 |
2005年 | 41篇 |
2004年 | 31篇 |
2003年 | 23篇 |
2002年 | 22篇 |
2001年 | 14篇 |
2000年 | 16篇 |
1999年 | 15篇 |
1998年 | 19篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 20篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 17篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 15篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1957年 | 4篇 |
1936年 | 4篇 |
排序方式: 共有1057条查询结果,搜索用时 15 毫秒
41.
Chowdhury Debasruti Bose Navonil Ghosh Dipankar Basu Mousumi 《Optical and Quantum Electronics》2017,49(9):1-12
Optical and Quantum Electronics - The nonlinear scattering of two non-collinear Gaussian pulses with different central frequencies and lengths, incident on the periodic stacks of semiconductor... 相似文献
42.
We study, using fluorescence correlation spectroscopy, translational diffusion in molecularly thin liquids confined within a surface forces apparatus. The diffusion coefficient decreases exponentially from the edges towards the center of the Hertzian contact and further suggests the presence of a small number of distinct diffusion processes. This holds alike a crystallizable fluid (OMCTS) and a glass-former (1,2-propane diol), both of which displayed static friction. We conclude that friction, the average of an ensemble of molecules, masked massively heterogeneous molecular mobility. 相似文献
43.
44.
Kalyan Kali Sengupta Biswanath Basu Shipra Sengupta Sanghamitra Nandi 《Polyhedron》1983,2(10):983-986
Hypophosphite ion is oxidised by Au(III) in aqueous hydrochloric acid to give phosphorus acid and Au(I). The kinetics of the reaction has been studied spectrophotometrically in the UV region at different temperatures. The oxidation of hypophosphorous acid is first order with respect to both Au(III) and substrate. Hydrogen ion has no effect on the rate in acid media (0.15–1.0)M. The energy and entropy of activations are 128 ± 3.0kJ mol?1 and 135.8 ± 6.5 JK?1 mol?1 respectively. The results are interpreted in terms of the probable formation of intermediate Au(lI). 相似文献
45.
The development of the theory of electron capture processes in ion-atom collisions is reviewed in the present work. The formal theory of scattering is used to obtain the Born and the distorted wave Born series for the rearrangement scattering matrix. On the basis of these series, the applications of the first and second Born approximation, the OBK approximation, the DWBA and the Padé approximants to electron capture processes are discussed. The impulse approximation, the Faddeev method and the second order potential method are also explained. The results of the investigations of the high energy behaviour of the charge transfer cross section based on the Faddeev-Watson multiple scattering expansion are analysed.The methods of molecular and atomic eigenfunction expansions are presented and their relative merits discussed. The semi-classical treatment for determining the differential electron capture probability is reviewed. Results obtained in works utilising expansions in Sturmian, Gaussian and pseudo-state wave functions are also presented. An integral equation approach to the close coupling approximation is described. The field theoretic approach to investigate the electron capture process is discussed in the last section.The results obtained by different theoretical methods are compared with available experimental results. 相似文献
46.
A simple method for the amperometric estimation of N-cyclohexyl-2-benzothiazole sulphenamide, N-dicyclohexyl-2-benzothiazole sulphenamide, 2-(morpholinothio)benzothiazole and N-tert.-butyl-2-benzothiazole sulphenamide is reported. The results are obtained within 5 min and are correct within +/- 2.0%. 相似文献
47.
X-ray photoemission spectra of vacuum cleaved LiC6, prepared from highly oriented pyrolytic graphite, provide a direct measure of the filling of the graphite π bands by electrons from Li. The resulting Fermi energy shift is in agreement with recent band structure calculations and indicates near unity charge transfer from Li. Core level spectra exhibit shifts compatible with the expected charge transger and line shapes showing strong asymmetries resulting from the metallic character of this compound. 相似文献
48.
B. K. Basu 《Czechoslovak Journal of Physics》1978,28(4):374-384
A set of recurrence relations connecting the matrix elements of finite transformation belonging to the same irreducible representation of SU(4) is used to obtain a wide class of matrix elements. An expression for the Clebsch-Gordan coefficient is obtained by integrating the product of three matrix elements belonging to three different irreducible representations of the group. The symmetry properties of the matrix elements and the Clebsch-Gordan coefficients are discussed.The author is grateful to Professors S.Datta Majumdar and G.Bandyopadhyay of the Department of Physics, I.I.T., Kharagpur, for many helpful discussions. This work was supported by the C.S.I.R., Government of India. 相似文献
49.
Sengupta T Dutta Choudhury S Basu S 《Journal of the American Chemical Society》2004,126(34):10589-10593
The interaction between 2'-deoxyadenosine and the model antitumor drug menadione has been studied in organic solvent and in micellar medium. The aim of the work is to elucidate the mechanism of this drug-nucleoside interaction and to determine the environmental effects. Laser flash photolysis and magnetic field effect are used to detect the transients and their spin states. The results indicate that H atom transfer and electron transfer are the operative mechanisms depending upon the medium. 相似文献
50.