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   1527篇
  免费   5篇
  国内免费   3篇
化学   810篇
晶体学   22篇
力学   45篇
数学   212篇
物理学   446篇
  2022年   17篇
  2021年   21篇
  2020年   23篇
  2019年   26篇
  2018年   36篇
  2017年   48篇
  2016年   56篇
  2015年   26篇
  2014年   36篇
  2013年   77篇
  2012年   57篇
  2011年   59篇
  2010年   50篇
  2009年   58篇
  2008年   50篇
  2007年   44篇
  2006年   36篇
  2005年   34篇
  2004年   34篇
  2003年   37篇
  2002年   32篇
  2001年   38篇
  2000年   32篇
  1999年   30篇
  1998年   21篇
  1997年   15篇
  1996年   16篇
  1995年   15篇
  1994年   16篇
  1992年   21篇
  1990年   17篇
  1989年   13篇
  1988年   14篇
  1986年   14篇
  1985年   12篇
  1983年   17篇
  1982年   25篇
  1981年   21篇
  1980年   20篇
  1979年   22篇
  1978年   16篇
  1977年   16篇
  1976年   25篇
  1975年   18篇
  1974年   18篇
  1973年   20篇
  1972年   28篇
  1971年   15篇
  1970年   16篇
  1969年   14篇
排序方式: 共有1535条查询结果,搜索用时 15 毫秒
41.
An experimental study of the characteristics of the explosion of mixtures of ammonium perchlorate, aluminum, and nitromethane with a large excess of aluminum (1.45 to 1.66 g/cm3 in density) confined in plastic enclosures and immersed in small elastic-wall reservoirs with water is conducted. It is shown that composite charges, 20 mm in diameter, surrounded by a water layer of thickness 20–30 cm and detonate in a nonideal detonation mode. High-speed cinematography records show the possibility of the intense mixing of the detonation products with the surrounding water and of the burning of excess aluminum particles in a heterogeneous cloud. The time scales of the development of secondary energy release by burning of aluminum particles in water are estimated. The possibility of controlling the characteristics of the pressure waves generated by the explosion, for example, by means of a preliminary bubbling of the water with air near the charge, is demonstrated.  相似文献   
42.
The dichroic effect (“rotated” polarization) in the reflectivity from a magnetically ordered sample is experimentally studied at the station PHASE of the Kurchatov Synchrotron Radiation Source. The experiments are performed for the Gd0.23Co0.77 film, which has a compensation temperature Tcomp ≈ 433 K, using linearly polarized radiation of the photon energy of 7930 eV (L2 absorption edge of gadolinium) at room temperature. The developed theory of reflectivity accounted for the magnetic contributions to the scattering amplitude predicts the appearance of a peak for the orthogonal (to the incident polarization) polarization of the reflected radiation near the critical angle of the total external reflection. The experiment reveals the significant difficulties because of the incomplete σ polarization of the synchrotron beam, the beam instability, and so on. Therefore, a rotated-polarization peak has been detected near the critical angle but at the limits of the measurement accuracy. In principle, our experimental technique could be an alternative to circular polarization experiments, which are widely used at synchrotrons to study magnetic ordering. However, as we have shown, it makes high demands of the radiation source parameters.  相似文献   
43.
In this paper, we focus on the study of two-dimensional plate dynamics on the Lobachevskii plane L 2. First of all, we consider the free motion of such a plate, which is a pseudospherical analog of dynamics of the Euler top, and also present an analog of the Euler–Poisson equations enabling us to study the motion of the body in potential force fields having rotational symmetry. We present a series of integrable cases, having analogs in Euclidean space, for different fields. Moreover, in the paper, a partial qualitative analysis of the dynamics of free motion of a plate under arbitrary initial conditions is made and a number of computer illustrations are presented which show a substantial difference of the motion from the case of Euclidean space. The study undertaken in the present paper leads to interesting physical consequences, which enable us to detect the influence of curvature on the body dynamics.  相似文献   
44.
45.
The bootstrap effect is observed in the pseudoliving radical copolymerization of styrene and acrylic acid mediated by a macroinitiator: the adduct of poly(acrylic acid) with a nitroxide radical. In this case, the macroinitiator serves as a peculiar “microreactor” with an increased local concentration of acrylic acid; as a result, the apparent activity of acrylic acid is higher than that in copolymerization mediated by low-molecular-mass initiators.  相似文献   
46.
Journal of Mathematical Chemistry - We mathematically analyze the solutions to the dynamical system induced by the two-step exponential (growth-)decay (2SED) reaction network involving three...  相似文献   
47.
Russian Journal of Applied Chemistry - At elevated temperatures (130 and 180°C) in hydrothermal autoclave conditions, the possibility of deep extraction of noble metals from poor intermediate...  相似文献   
48.
Russian Journal of Applied Chemistry - The influence of parameters of the dry-jet wet spinning process was studied on properties of porous polysulfone hollow fiber membranes. The air gap distance,...  相似文献   
49.
The simple scaling theory of weakly-charged polyelectrolyte brush (the layer of polyelectrolyte chains grafted at one end onto an impermeable surface) immersed into a good solvent has been developed.The asymptotic scaling dependences of the free layer thickness on charge density and solvent strength are obtained. The behavior of polyelectrolyte brush subjected to normal and tangential external forces is considered. New “polyelectrolyte effect” is predicted: shear of a free polyelectrolyte brush leads to a decrease in brush thickness in contrast to the case of a free neutral brush. Such behavior is equivalent to that of a neutral brush subjected to external normal stretching force. This force in the case of polyelectrolyte brush is created by the osmotic pressure of mobile counterions neutralizing grafted chain charges.  相似文献   
50.
Borisov  A. V.  Tsiganov  A. V. 《Doklady Physics》2020,65(3):90-93
Doklady Physics - In this paper, we consider the motion of a nonholonomic Chaplygin sphere on a plane in a constant magnetic field under the assumption that the sphere has dielectric and...  相似文献   
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