首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8833篇
  免费   26篇
  国内免费   3篇
化学   5525篇
晶体学   117篇
力学   290篇
数学   1157篇
物理学   1773篇
  2020年   86篇
  2019年   107篇
  2018年   170篇
  2017年   166篇
  2016年   200篇
  2014年   199篇
  2013年   240篇
  2012年   248篇
  2011年   251篇
  2010年   248篇
  2009年   228篇
  2008年   228篇
  2007年   233篇
  2006年   170篇
  2005年   155篇
  2004年   152篇
  2003年   151篇
  2002年   156篇
  2001年   120篇
  2000年   85篇
  1998年   116篇
  1997年   112篇
  1995年   119篇
  1994年   106篇
  1993年   108篇
  1992年   123篇
  1991年   132篇
  1990年   124篇
  1989年   124篇
  1988年   118篇
  1987年   150篇
  1986年   156篇
  1985年   135篇
  1984年   133篇
  1983年   143篇
  1982年   137篇
  1981年   141篇
  1980年   129篇
  1979年   160篇
  1978年   194篇
  1977年   247篇
  1976年   273篇
  1975年   194篇
  1974年   190篇
  1973年   198篇
  1972年   190篇
  1971年   153篇
  1970年   131篇
  1969年   112篇
  1968年   120篇
排序方式: 共有8862条查询结果,搜索用时 15 毫秒
11.
Differential absorption spectra of RbAg4I5 have been measured in the exciton absorption region of AgI within the temperature range 27–250 °C. In the same temperature range, the temperature behavior of the heat capacity of RbAg4I5, Rb2AgI3, and KAg4I5 have been obtained by differential scanning calorimetry. An analysis of the results suggests that, in AgI microcrystals less than r cr in size, the upper boundary for stability of the low-temperature β modification is higher by several tens of degrees. Fiz. Tverd. Tela (St. Petersburg) 40, 852–854 (May 1998)  相似文献   
12.
Contact melting (CM) in the lead-tellurium system is considered. Spontaneous temperature elevation is observed as a result of the exothermic reaction of lead telluride formation in the contact site. The effects of direct current (dc) and dopants on the CM temperature are studied.  相似文献   
13.
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   
14.
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   
15.
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   
16.
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   
17.
18.
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   
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号