全文获取类型
收费全文 | 3849篇 |
免费 | 69篇 |
国内免费 | 4篇 |
专业分类
化学 | 1674篇 |
晶体学 | 48篇 |
力学 | 116篇 |
数学 | 436篇 |
物理学 | 1648篇 |
出版年
2022年 | 44篇 |
2021年 | 83篇 |
2020年 | 74篇 |
2019年 | 86篇 |
2018年 | 131篇 |
2017年 | 102篇 |
2016年 | 148篇 |
2015年 | 86篇 |
2014年 | 113篇 |
2013年 | 178篇 |
2012年 | 162篇 |
2011年 | 163篇 |
2010年 | 162篇 |
2009年 | 132篇 |
2008年 | 192篇 |
2007年 | 170篇 |
2006年 | 152篇 |
2005年 | 155篇 |
2004年 | 111篇 |
2003年 | 115篇 |
2002年 | 99篇 |
2001年 | 99篇 |
2000年 | 88篇 |
1999年 | 50篇 |
1998年 | 49篇 |
1997年 | 50篇 |
1996年 | 44篇 |
1995年 | 24篇 |
1994年 | 28篇 |
1993年 | 39篇 |
1992年 | 39篇 |
1991年 | 46篇 |
1990年 | 34篇 |
1989年 | 39篇 |
1988年 | 33篇 |
1987年 | 28篇 |
1985年 | 31篇 |
1984年 | 32篇 |
1983年 | 28篇 |
1982年 | 26篇 |
1981年 | 28篇 |
1979年 | 34篇 |
1978年 | 31篇 |
1977年 | 43篇 |
1976年 | 34篇 |
1975年 | 28篇 |
1974年 | 29篇 |
1973年 | 34篇 |
1972年 | 29篇 |
1971年 | 28篇 |
排序方式: 共有3922条查询结果,搜索用时 8 毫秒
71.
Hsueh SY Muller D Tang J Winston R Zapalac G Swallow EC Berge JP Brenner AE Grafstrom P Jastrzembski E Lach J Marriner J Raja R Smith VJ McCliment E Newsom C Anderson EW Denisov AS Grachev VT Kulikov AV Schegelsky VA Seliverstov DM Smirnov NN Terentyev NK Tkatch II Vorobyov AA Cooper PS Razis P Teig LJ 《Physical review letters》1985,54(22):2399-2402
72.
73.
74.
The main concepts of the nature of electronically excited states in polyatomic molecules and the intramolecular and intermolecular processes of their evolution are reported. The dependence of the probabilities of these processes on the electronic structure of the molecule is considered. Possible mechanisms of the dissociation of electronically excited molecules with bond cleavage are discussed, and the theoretical results of this consideration are given. The experimental data obtained by the authors are interpreted. In this case, attention is focused on C-H-bond photodissociation processes in a condensed phase, which are the best studied processes. The dissociation of other bonds is briefly discussed. 相似文献
75.
76.
A purely group-theoretical approach (for which the symmetric group plays a central role), based upon the use of properties of fractional-parentage coefficients and isoscalar factors, is developed for the derivation of the Coulomb energy averaged over the states, with a definite spin, arising from an atomic configuration nlN. © 1995 John Wiley & Sons, Inc. 相似文献
77.
Kolen'ko YV Kovnir KA Gavrilov AI Garshev AV Meskin PE Churagulov BR Bouchard M Colbeau-Justin C Lebedev OI Van Tendeloo G Yoshimura M 《The journal of physical chemistry. B》2005,109(43):20303-20309
Mesoporous nanosized TiO2 and Zn(x)Ti(1-x)O(2-x) solid solution having a Zn content below 10 mol % with a particles size between 13 and 17 nm are prepared by a template-free sol-gel method followed by high-temperature supercritical drying in 2-propanol. The structural, textural, and electronic properties of the obtained nanomaterials are methodically investigated by using XRD, SEM, TEM, ED, HREM, EDX, ICP-OES, N(2) adsorption-desorption, Raman spectroscopy, and diffuse reflectance UV-vis spectroscopy. It is shown that the proposed synthesis technique leads to the formation of a Zn(x)Ti(1-x)O(2-x) solid solution based on the anatase crystal structure rather than a two-phase sample. High-resolution electron microscopy and electron diffraction indicate that the distribution of zinc atoms over the anatase structure does not lead to a considerable deformation of the crystal structure. 相似文献
78.
The effects of usual low-intensity continuous (lambda = 254 nm, I = 10 W/m2) UV radiation and high-intensity laser nanosecond (lambda = 266 nm, tau p = 10 ns, I = 10(9) W/m2) or picosecond (lambda = 266 nm, tau p = 23 ps, I = 10(12) W/m2) UV radiation on Venezuelan equine encephalomyelitis virus (a member of the Togaviridae family) were compared. The quantum yields of infectivity inactivation, pyrimidine dimer formation and RNA-protein crosslinking were determined. 相似文献
79.
L. D. Smirnov K. M. Dyumaev N. I. Shuikin I. F. Bel'skii 《Russian Chemical Bulletin》1962,11(12):2148-2149
Summary A new method was proposed for the synthesis of 2,4,6-trialky1-3-hydroxypyridines by the reactions of 3,5-dialkyl-2-acylfurans with ammonia. 相似文献
80.
Yu. M. Smirnov 《High Energy Chemistry》2003,37(3):129-135
The dissociative excitation of MnII spectral lines and MnCl spectral bands upon e–MnCl2 collisions was experimentally studied. Dissociative excitation is most effective for the low-lying 5
P° and 7
P° levels of MnII. Two sequences = 0 in the – systems of the MnCl molecule were detected. Possible pathways of dissociative excitation of MnII are discussed. 相似文献