全文获取类型
收费全文 | 5671篇 |
免费 | 52篇 |
国内免费 | 30篇 |
专业分类
化学 | 3279篇 |
晶体学 | 58篇 |
力学 | 245篇 |
数学 | 887篇 |
物理学 | 1284篇 |
出版年
2021年 | 77篇 |
2020年 | 92篇 |
2019年 | 94篇 |
2018年 | 135篇 |
2017年 | 162篇 |
2016年 | 152篇 |
2015年 | 55篇 |
2014年 | 123篇 |
2013年 | 248篇 |
2012年 | 176篇 |
2011年 | 216篇 |
2010年 | 189篇 |
2009年 | 204篇 |
2008年 | 179篇 |
2007年 | 189篇 |
2006年 | 148篇 |
2005年 | 114篇 |
2004年 | 124篇 |
2003年 | 129篇 |
2002年 | 138篇 |
2001年 | 102篇 |
2000年 | 82篇 |
1999年 | 60篇 |
1998年 | 60篇 |
1997年 | 60篇 |
1995年 | 94篇 |
1994年 | 105篇 |
1993年 | 82篇 |
1992年 | 59篇 |
1991年 | 83篇 |
1990年 | 87篇 |
1989年 | 79篇 |
1988年 | 62篇 |
1987年 | 79篇 |
1986年 | 66篇 |
1985年 | 87篇 |
1984年 | 116篇 |
1983年 | 74篇 |
1982年 | 88篇 |
1981年 | 69篇 |
1980年 | 70篇 |
1979年 | 110篇 |
1978年 | 101篇 |
1977年 | 105篇 |
1976年 | 113篇 |
1975年 | 92篇 |
1974年 | 60篇 |
1973年 | 85篇 |
1972年 | 65篇 |
1970年 | 67篇 |
排序方式: 共有5753条查询结果,搜索用时 15 毫秒
61.
We revealed the changes in the γ-luminescence spectra under the influence of a thermal radiation field on high-purity alkali-silicate
glasses (I) and those with addition of Fe3+ ions (II). We explain the obtained results within the framework of the L-model of edge absorption and electron-hole recombination
processes.
Samarkand State University, 15, Universitetskii Bul., Samarkand, 703004, Republic of Uzbekistan. Translated from Zhurnal Prikladnoi
Spektroskopii, Vol. 65, No. 3, pp. 453–455, May–June, 1998. 相似文献
62.
Sh. A. Kasymov 《Journal of Mathematical Sciences》1993,66(5):2488-2491
We consider the formation of a boundary layer above a semi-infinite plate that moves with velocity Vt8=At
n
in a viscous incompressible fluid. The problem is solved by Meksyn's asymptotic method. First, second, and third approximation equations are obtained. A numerical calculation is performed for various n, and especially interesting results are obtained for –0.5 < n < 0. The numerical solution of the third approximation equation is consistent with other known results.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 65, pp. 51–55, 1988. 相似文献
63.
The photon polarization operator is computed in the presence of a constant external chromomagnetic field in nonrelativistic approximation. The found branching points of the polarization operator are compared with the minimal energy necessary for creation of scalar colored particles. The absence of confinement for such quarks in the field under consideration is noted.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 23–26, October, 1990. 相似文献
64.
Theoretical and experimental aspects of the study of the e-- problem in effects of neutral weak currents in colliding e+e– beams in the region of the Z resonance are discussed. Quantities that describe the degree of violation of e-- universality are analyzed. In particular, it is shown that by measuring the spin asymmetry for angles 160° it is possible to determine the degree of violation ofl-e universality =g
A
e
g
V
l
–g
V
e
g
A
l
to an accuracy of up to 0.01.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 88-91, May, 1989. 相似文献
65.
66.
Sh. A. Samsoniya M. V. Trapaidze N. A. Kuprashvili N. Sh. Samsoniya N. N. Suvorov 《Chemistry of Heterocyclic Compounds》1994,30(8):901-904
Summary 2, 9 -Di (carbohydrazide)-1 H, IOH-benzo[elpyrrolo[3, 2-g]indole and 2, 9-di (carbohydrazide)-3H, 8H-indolo[4, 5-e]indole have been prepared. Nitrosation of the dihydrazides has been effected. The aryl azides do not undergo the curtius rearrangment.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1048-1051, August, 1994.Communication 33, see [1]. 相似文献
67.
Chemistry of Natural Compounds - The epigeal part ofArtemisia santolina Schrenk has yielded a new sesquiterpene lactone, artesin, C14H22O3, having the structure... 相似文献
68.
U. G. Magomedbekov Kh. M. Gasanova U. G. Gasangadzhieva K. A. Abdulkhamidov S. Sh. Mutsalova 《Moscow University Chemistry Bulletin》2007,62(4):230-236
A possible mechanism of 1,4-naphthalenediol oxidation in the oscillatory regime has been considered, and a mathematical model describing the kinetics has been developed. Based on a thermodynamic Lyapunov function, it has been shown that the source of chemical instabilities is in the existence of autocatalytic steps and dynamic feedbacks. Qualitative analysis and numerical solution of the set of differential equations that model the reaction kinetics have been performed. The character of the stationary state and the possibility of bifurcations have been determined. The mathematical model satisfactorily describes the processes occurring in the system. 相似文献
69.
70.
Alkynyl-substituted indene was first used as a ligand for the synthesis of transition metal complexes. ansa-Zirconocenes containing ethylene and dimethylsilylene bridges were synthesized starting from 2-(phenylethynyl)-1H-indene. The structure of the former compound was established by X-ray diffraction.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 68–73, January, 2007. 相似文献