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   2954篇
  免费   125篇
  国内免费   12篇
化学   2124篇
晶体学   15篇
力学   107篇
数学   406篇
物理学   439篇
  2023年   32篇
  2022年   22篇
  2021年   64篇
  2020年   70篇
  2019年   70篇
  2018年   46篇
  2017年   37篇
  2016年   88篇
  2015年   82篇
  2014年   82篇
  2013年   133篇
  2012年   188篇
  2011年   209篇
  2010年   115篇
  2009年   97篇
  2008年   191篇
  2007年   169篇
  2006年   182篇
  2005年   153篇
  2004年   96篇
  2003年   92篇
  2002年   67篇
  2001年   60篇
  2000年   38篇
  1999年   32篇
  1998年   40篇
  1997年   29篇
  1996年   34篇
  1995年   23篇
  1994年   22篇
  1993年   26篇
  1992年   35篇
  1991年   22篇
  1990年   15篇
  1989年   16篇
  1988年   13篇
  1987年   19篇
  1986年   25篇
  1985年   16篇
  1984年   24篇
  1983年   17篇
  1982年   20篇
  1981年   28篇
  1980年   31篇
  1978年   27篇
  1977年   24篇
  1976年   21篇
  1975年   16篇
  1974年   13篇
  1972年   12篇
排序方式: 共有3091条查询结果,搜索用时 406 毫秒
101.
102.
Annals of Operations Research - We consider the use of the new C-130J-30 aircraft for long distance (strategic) cargo movement. Currently, only large aircraft, the C-5 and the C-17, are identified...  相似文献   
103.
104.
Different methods for the interpretation of linear dichroic spectra of molecules incorporated in uniaxial matrices are discussed. A method based on the combination of both polarized absorption and emission measurements is described for the resolution of absorption and emission spectra into their different polarized components, and for the investigation of molecular distributions in the oriented matrix. The distributions of some planar molecules of different shapes incorporated in stretched polyethylene films are presented.  相似文献   
105.
106.
107.
Recent measurements of charge-dependent azimuthal correlations in high-energy heavy-ion collisions have indicated charge-separation signals perpendicular to the reaction plane, and have been related to the chiral magnetic effect(CME). However, the correlation signal is contaminated with the background caused by the collective motion(flow) of the collision system, and an effective approach is needed to remove the flow background from the correlation. We present a method study with simplified Monte Carlo simulations and a multi-phase transport model,and develop a scheme to reveal the true CME signal via event-shape engineering with the flow vector of the particles of interest.  相似文献   
108.
We present the software package MO VI PAC for calculations of vibrational spectra, namely infrared, Raman, and Raman Optical Activity (ROA) spectra, in a massively parallelized fashion. MO VI PAC unites the latest versions of the programs SNF and AKIRA alongside with a range of helpful add‐ons to analyze and interpret the data obtained in the calculations. With its efficient parallelization and meta‐program design, MO VI PAC focuses in particular on the calculation of vibrational spectra of very large molecules containing on the order of a hundred atoms. For this purpose, it also offers different subsystem approaches such as Mode‐ and Intensity‐Tracking to selectively calculate specific features of the full spectrum. Furthermore, an approximation to the entire spectrum can be obtained using the Cartesian Tensor Transfer Method. We illustrate these capabilities using the example of a large π‐helix consisting of 20 (S)‐alanine residues. In particular, we investigate the ROA spectrum of this structure and compare it to the spectra of α‐ and 310‐helical analogs. © 2012 Wiley Periodicals, Inc.  相似文献   
109.
110.
Thermodynamic properties of Dysprosium rhodite (DyRhO3) are measured in the temperature range from 900 to 1,300 K using a solid-state electrochemical cell incorporating yttria-stabilized zirconia as the electrolyte. The standard Gibbs free energy of formation of DyRhO3 with O-type perovskite structure from its components binary oxides, Dysprosia with C-rare earth structure and β-Rh2O3 with orthorhombic structure, can be represented by the equation: $$ {{{\varDelta G_{{f\left( {ox} \right)}}^o\left( {\pm 182} \right)}} \left/ {{{\mathrm{J} ~ \mathrm{mo}}{{\mathrm{l}}^{{ - 1}}}}} \right.} = - 52710 + 3.821\left( {{{T} \left/ {\mathrm{K}} \right.}} \right). $$ By using the thermodynamic data for DyRhO3 from experiment and auxiliary data for other phases from the literature, the phase relations in the system Dy-Rh-O are computed. Thermodynamic data for intermetallic phases in the binary system Dy-Rh, required for constructing the chemical potential diagrams, are evaluated using calorimetric data available in the literature for three intermetallics and Miedema’s model, consistent with the phase diagram. The results are presented in the form of Gibbs triangle, oxygen potential–composition diagram, and three-dimensional chemical potential diagram at 1,273 K. Temperature–composition diagrams at constant oxygen partial pressures are also developed. The decomposition temperature of DyRhO3 is 1,732 (±2.5) K in pure oxygen and 1,624 (±2.5) K and in air at standard pressure.  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