全文获取类型
收费全文 | 87400篇 |
免费 | 381篇 |
国内免费 | 383篇 |
专业分类
化学 | 30313篇 |
晶体学 | 908篇 |
力学 | 7012篇 |
数学 | 33114篇 |
物理学 | 16817篇 |
出版年
2019年 | 136篇 |
2018年 | 10620篇 |
2017年 | 10428篇 |
2016年 | 6290篇 |
2015年 | 961篇 |
2014年 | 518篇 |
2013年 | 614篇 |
2012年 | 4074篇 |
2011年 | 10828篇 |
2010年 | 5909篇 |
2009年 | 6307篇 |
2008年 | 6846篇 |
2007年 | 9006篇 |
2006年 | 430篇 |
2005年 | 1478篇 |
2004年 | 1694篇 |
2003年 | 2124篇 |
2002年 | 1170篇 |
2001年 | 368篇 |
2000年 | 378篇 |
1999年 | 225篇 |
1998年 | 304篇 |
1997年 | 254篇 |
1996年 | 274篇 |
1995年 | 232篇 |
1994年 | 185篇 |
1993年 | 204篇 |
1992年 | 172篇 |
1991年 | 195篇 |
1990年 | 172篇 |
1989年 | 182篇 |
1988年 | 177篇 |
1987年 | 205篇 |
1986年 | 212篇 |
1985年 | 183篇 |
1984年 | 173篇 |
1983年 | 181篇 |
1982年 | 178篇 |
1981年 | 174篇 |
1980年 | 178篇 |
1979年 | 205篇 |
1978年 | 228篇 |
1977年 | 267篇 |
1976年 | 289篇 |
1975年 | 208篇 |
1974年 | 199篇 |
1973年 | 218篇 |
1972年 | 208篇 |
1971年 | 158篇 |
1970年 | 136篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
41.
We propose a general idea of obtaining different chains of coupled oscillators with chaotic buffering. As examples, we consider chains of diffusively coupled generalized cubic Schrödinger equations and nonlinear telegraph equations. We also give examples of systems that have an infinite-dimensional chaotic attractor. 相似文献
42.
The character of the localization of the wave functions of an icosahedral quasicrystal is investigated in the tight-binding
approximation. It is found that the wave functions exhibit “critical behavior”: they are neither localized, as in the case
of Anderson localization, nor delocalized, as in the case of Bloch states.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 8, 559–563 (25 October 1996) 相似文献
43.
M. Kh. Khankhasayev 《Czechoslovak Journal of Physics》1989,39(8):836-842
The review of new theoretical and experimental results in the field of the pion-nucleus interaction which are presented in the contributed papers at the IV International symposium Mesons and Light Nuclei (Bechyn, 1988) is given. The discussion covers a wide area of problems from the -nucleon interaction to the pion interaction with light nuclei at low and intermediate energies.Rapporteur talk at the symposium Mesons and Light Nuclei, IV, Bechyn, Czechoslovakia, September 5–10, 1988. 相似文献
44.
R. A. Gavar L. Kh. Baumane Ya. P. Stradyn' S. A. Giller 《Chemistry of Heterocyclic Compounds》1974,10(3):280-284
Anion radicals of 2-vinylene derivatives of 5-nitrofuran were obtained by electrochemical generation. The hyperfine structure (hfs) of the ESR spectra of these anion radicals indicates delocalization of the unpaired electron over their entire π-electron system. The effect of the vinylene grouping on the distribution of the unpaired electron in the anion radicals and on the distribution of the unpaired electron in the vinylene grouping itself was examined on the basis of the hfs constants. It was found that the vinylene grouping by localizing more than 10% of the density of the unpaired electron on itself reduces, by a factor of 1.4, the effect of substituents in the 2 position of 5-nitrofuran on the distribution of the spin of the unpaired electron in the nitrofuran framework. 相似文献
45.
46.
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
47.
48.
49.
50.