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   4448篇
  免费   34篇
  国内免费   2篇
化学   1943篇
晶体学   71篇
力学   134篇
数学   456篇
物理学   1880篇
  2023年   13篇
  2022年   50篇
  2021年   96篇
  2020年   76篇
  2019年   138篇
  2018年   197篇
  2017年   194篇
  2016年   206篇
  2015年   93篇
  2014年   172篇
  2013年   279篇
  2012年   245篇
  2011年   296篇
  2010年   305篇
  2009年   275篇
  2008年   291篇
  2007年   254篇
  2006年   279篇
  2005年   165篇
  2004年   140篇
  2003年   84篇
  2002年   85篇
  2001年   93篇
  2000年   113篇
  1999年   68篇
  1998年   87篇
  1997年   58篇
  1996年   18篇
  1995年   5篇
  1994年   4篇
  1991年   4篇
  1990年   4篇
  1988年   2篇
  1987年   3篇
  1985年   7篇
  1984年   4篇
  1983年   6篇
  1981年   8篇
  1980年   5篇
  1979年   6篇
  1978年   8篇
  1977年   8篇
  1976年   5篇
  1975年   5篇
  1974年   3篇
  1973年   4篇
  1972年   4篇
  1971年   3篇
  1969年   4篇
  1965年   2篇
排序方式: 共有4484条查询结果,搜索用时 296 毫秒
1.
2.
Russian Journal of General Chemistry - Highly dispersed CaO has been synthesized by heating an aqueous solution of calcium nitrate and D-glucose up to 800°C. Calcium oxide is formed with an...  相似文献   
3.
Vorob’ev  N. T.  Lantsetova  E. D. 《Mathematical Notes》2021,110(5-6):655-665
Mathematical Notes - It is proved that the lattice of all Fitting classes of finite groups is not distributive, and conditions under which Fitting classes satisfy the distributive and modular laws...  相似文献   
4.
5.
This paper reports on the first experimental observation of quantum-well states and sp-type resonances in thin single-crystal gold, silver, and copper layers formed on single-crystal W(110) surfaces, which result from spatial localization of Bloch-type electronic wave functions in a quantum well with potential barriers at the vacuum/metal and metal/W(110) interfaces. The quantization of the valence-band electronic structure in Au/W(110), Ag/W(110), and Cu/W(110) systems was studied experimentally using angle-resolved photoelectron spectroscopy.  相似文献   
6.
The enthalpies of reactions of La2CoO4(cr) and CoCl2(cr) with hydrochloric acid were measured with an isothermal-jacket calorimeter. The results obtained and the available literature data were used to calculate the standard enthalpy of formation of La2CoO4(cr) at 298.15 K, Δf H o = ?2179 ± 7 kJ/mol.  相似文献   
7.
The diffraction efficiency and the recording and relaxation times of dynamic reflection holograms, recorded in CdF2 crystals with bistable centers are studied experimentally in the temperature range 20–100°C. In the model experiments which measured the quality of the wave reflected from the hologram, the dynamic wavefront distortions are demonstrated to be efficiently compensated using a holographic corrector based on these crystals. CdF2 crystals with bistable centers are likely to be useful in solving problems of correction of laser light wavefront and image correction in observation telescopes with nonideal primary mirrors.  相似文献   
8.
The formation and decay of negative molecular ions of azafullerenes and their hydrogenated derivatives are investigated by mass spectrometry. The mechanisms of resonant electron capture and the lifetimes of negative molecular ions with respect to the electron autodetachment in azafullerene molecules are discussed. A comparative analysis of the data obtained for azafullerenes and hydrogenated fullerene derivatives is carried out.  相似文献   
9.
An analytical solution of a linearized problem of the emission of periodic internal waves by part of a plane which oscillates with a small amplitude in an arbitrary direction in a viscous exponentially stratified fluid is constructed. Solutions of the dispersion equation are given for all positions of the emitting surface (arbitrary, vertical, horizontal, and critical when one of the beam propagation directions is collinear with the emitting surface). The possibility of transition to the case of a uniform fluid, which is important for applications, is analyzed.  相似文献   
10.
The lattice IR reflection spectra of a ZnTe/Zn0.8Cd0.2Te superlattice measured at temperatures of 300 and 10 K are analyzed. The ZnTe/Zn0.8Cd0.2Te superlattice is grown by molecular-beam epitaxy on a GaAs substrate with a ZnTe buffer layer. It is found that the lattice IR reflection spectra of the studied structure exhibit only one reflection band. Dispersion analysis of the experimental spectrum has revealed the presence of one lattice TO mode close in frequency to the mode of pure ZnTe. This result is explained by a shift in the frequency of the lattice modes of the ZnTe and Zn0.8Cd0.2Te layers of the superlattice toward each other. In turn, this shift is caused by internal elastic stresses in the superlattice due to a mismatch between the lattice parameters of the materials of these layers.  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