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   369篇
  免费   1篇
化学   267篇
晶体学   10篇
力学   4篇
数学   10篇
物理学   79篇
  2022年   3篇
  2021年   14篇
  2020年   10篇
  2019年   16篇
  2018年   10篇
  2017年   16篇
  2016年   16篇
  2015年   10篇
  2014年   12篇
  2013年   16篇
  2012年   7篇
  2011年   13篇
  2010年   12篇
  2009年   16篇
  2008年   10篇
  2007年   14篇
  2006年   5篇
  2005年   11篇
  2004年   13篇
  2003年   7篇
  2002年   20篇
  2001年   14篇
  2000年   5篇
  1999年   2篇
  1997年   2篇
  1995年   3篇
  1992年   7篇
  1991年   5篇
  1990年   2篇
  1988年   2篇
  1987年   4篇
  1985年   6篇
  1984年   3篇
  1983年   5篇
  1982年   4篇
  1981年   4篇
  1980年   2篇
  1979年   2篇
  1977年   3篇
  1976年   4篇
  1975年   4篇
  1974年   2篇
  1973年   5篇
  1972年   6篇
  1970年   7篇
  1964年   1篇
  1963年   1篇
  1961年   1篇
  1960年   1篇
  1957年   4篇
排序方式: 共有370条查询结果,搜索用时 15 毫秒
21.
The structure of EK-181 (RUSFER-EK-181, low-activation) and ChS-139 12% Cr ferritic–martensitic steels is investigated and their mechanical properties are tested after long-term (13500 h) aging at 450 and 620°C. The microstructure of the steels exhibits a high thermal stability, which provides the retention of their initial short-term mechanical properties at test temperatures.  相似文献   
22.
It is shown that the occurrence of metallic conductivity in polymers is due to their electrification. In particular, the current density depends on the electron work function of metallic electrodes which are in contact with the polymer.  相似文献   
23.
This paper deals with X-ray photoelectron and electron microscopy studies of the structure of carbon–metal-containing micro- and nanotubulenes. Ab initio quantum-chemical calculations were performed to analyze the possibility and mechanism of tubulene formation.  相似文献   
24.
A method for preparing a multicapillary column with a porous layer based on the styrene-divinylbenzene copolymer has been developed. The column makes it possible to quickly separate C1–C4 hydrocarbons and oxygen-containing compounds. The main chromatographic properties of the columns were studied.  相似文献   
25.
Optimal conditions were found for the preparation of copper nanoparticles in aqueous solution via reduction of copper(II) ions with hydrazine hydrate. The effects of ligand environment of copper(II) in the initial solution (hydrate, ammonia, citrate, and glycine complexes), concentration, pH, surfactants, temperature, and mode of heating were examined. The obtained colloidal systems were studied by optical spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, and atomic force microscopy. The examined colloids were found to contain generally spherical copper nanoparticles with a diameter of about 10 nm, which were coated with a copper(I) or copper(II) oxide and hydroxide film.  相似文献   
26.
27.
A method for preparation of divinylbenzene-styrene copolymer porous layer on the inner wall of a fused silica capillary was developed. Capillary gas chromatography was used to investigate the sorption capacity of copolymer film toward substances of various classes.  相似文献   
28.
The theoretical investigation of the hyper-Raman scattering by 2LO phonons is carried when the doubled energy of incident photons lies near the band gap of a semiconductor. The scattering process is considered, taking into account the Wannier excitons as intermediate states.  相似文献   
29.
30.
The problem of two-layer heavy inviscid fluid flow past a vortex in the presence of a semi-infinite plate on the interface when the fluids have different densities and velocities at infinity is solved in the linear approximation. The forces exerted on the vortex and the plate and the shape of the interface are determined as functions of the location of the vortex, its intensity, the Froude number, the free-stream density ratio and the velocities.  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