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   1348713篇
  免费   25797篇
  国内免费   7788篇
化学   671770篇
晶体学   20553篇
力学   74995篇
综合类   108篇
数学   241560篇
物理学   373312篇
  2021年   13523篇
  2020年   15923篇
  2019年   16045篇
  2018年   13663篇
  2016年   28260篇
  2015年   20882篇
  2014年   30393篇
  2013年   74282篇
  2012年   37986篇
  2011年   35371篇
  2010年   37716篇
  2009年   40148篇
  2008年   34746篇
  2007年   30552篇
  2006年   35352篇
  2005年   28974篇
  2004年   29740篇
  2003年   27978篇
  2002年   28825篇
  2001年   28582篇
  2000年   24729篇
  1999年   22499篇
  1998年   20944篇
  1997年   20976篇
  1996年   21069篇
  1995年   19146篇
  1994年   18608篇
  1993年   18102篇
  1992年   18311篇
  1991年   18526篇
  1990年   17745篇
  1989年   17808篇
  1988年   17409篇
  1987年   17424篇
  1986年   16290篇
  1985年   22736篇
  1984年   23914篇
  1983年   20051篇
  1982年   21679篇
  1981年   20878篇
  1980年   20251篇
  1979年   20527篇
  1978年   21737篇
  1977年   21411篇
  1976年   21087篇
  1975年   19750篇
  1974年   19415篇
  1973年   19829篇
  1972年   14321篇
  1967年   12621篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
902.
903.
Isochronous relaxation of tensile stresses is measured in a bulk Pd40Cu30Ni10P20 metallic glass in the initial state and after certain thermal treatments. The results of measurements are used to find the energy spectrum of irreversible structural relaxation, from which the temperature dependence of shear viscosity is then calculated. This dependence is also found independently from measurements of creep in the same glass. The calculated viscosity is shown to agree well with the experimental data.  相似文献   
904.
A suspension of ultrafine-dispersed nanodiamond was used for introducing (in particular, selectively) high-density centers of diamond nucleation on various substrates. High-quality doped diamond films to be used as electrochemistry electrodes were deposited from the gas phase in a microwave discharge on certain substrates treated using ultrafine-dispersed nanodiamond. A uniform distribution of nucleation centers with concentrations greater than 1010 cm-2 on silicon substrates was obtained. Electrochemical current-potential curves were measured for continuous films. Diamond meshes of different transparency were grown using selective nucleation. Successful production of high-quality doped diamond meshes gives grounds to consider them the most promising electrodes for use in electrochemistry.  相似文献   
905.
The translational nonequilibrium zone in a shock wave is considered for a gas consisting of light particles and a small addition of heavy particles. The gas is taken to be two-dimensional, and long-range forces are assumed to be absent. In the framework of this approximation, a program for molecular dynamics simulation of the gas is developed. It is applied to calculate a particle distribution function in the shock wave, to analyze the time evolution of the distribution function, and to study its dependence on the gas composition.  相似文献   
906.
The properties of nonrectifying AuGe/GaAs (Al0.4Ga0.6As) contacts exposed to heat treatment, 60Co γ radiation, and γ radiation combined with the application of an electrical bias are studied. A correlation between the type of interfacial interaction in the contacts and their resistance is found. Results obtained are explained in terms of a diffusion model with a movable boundary of the metal layer.  相似文献   
907.
The structure, composition, and mechanical properties of iron-alloyed TiC-TiNi composite materials are studied. When the titanium carbide framework is sintered with iron and then impregnated with titanium nickelide, iron atoms are found to diffuse into the matrix and form the B2 structure that is inhomogeneous (gradient) in chemical composition and properties and exhibits various temperatures of martensitic transformation. The latter fact shows up in the broadening of the martensitic transformation hysteresis and its shift toward low temperatures with increasing iron content. At room temperature, the strength properties of gradient-matrix TiC-TiNi composites are shown to increase with iron concentration.  相似文献   
908.
Russian Physics Journal -  相似文献   
909.
910.
The problem of dimensionality of time is considered. The space-time curvature is shown to result not only from the presence of the gravitational field but also from a certain other field whose potential is a positive value.  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