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   387篇
  免费   1篇
化学   346篇
晶体学   1篇
力学   2篇
数学   2篇
物理学   37篇
  2022年   3篇
  2021年   8篇
  2020年   3篇
  2019年   17篇
  2018年   12篇
  2017年   22篇
  2016年   20篇
  2015年   6篇
  2014年   11篇
  2013年   18篇
  2012年   24篇
  2011年   26篇
  2010年   18篇
  2009年   23篇
  2008年   14篇
  2007年   30篇
  2006年   18篇
  2005年   9篇
  2004年   11篇
  2003年   6篇
  2002年   6篇
  2001年   11篇
  2000年   2篇
  1998年   2篇
  1994年   3篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   2篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1983年   3篇
  1982年   1篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1974年   1篇
  1973年   6篇
  1972年   4篇
  1971年   3篇
  1970年   4篇
  1969年   3篇
  1968年   4篇
  1966年   1篇
  1964年   1篇
  1962年   1篇
排序方式: 共有388条查询结果,搜索用时 296 毫秒
1.
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity).  相似文献   
2.
3.
4.
5.
Wetting angles and limits of thermal stability of esters derived from pentaerythritol and perfluoro-, ω-chloropolyfluoro-, and perfluoropolyethercarboxylic acids were studied.  相似文献   
6.
Butadiene-styrene and acrylate latexes were studied as matrices for preparing colloidal silver. Colloidal-chemical and strength properties of the modified latexes and Primal E1950 latex films were studied. The heat resistance of these materials was determined.  相似文献   
7.
Conclusions Exchange reactions proceed in the olefin oxide-phenyl-hydroxyalkyl selenide system with the probable intermediate involvement of the selenonium salt.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2833–2835, December, 1982.  相似文献   
8.
Summary The design of new dynamic, axial-compression columns with a system for continous packed bed adjustment and monitoring of the floating adapter position is described. The columns are meant for liquid chromatography at low pressures (up to 8 bar) in aqueous and organic media with stationary phases of all types. The columns have adapter position pickups for continuous automatic monitoring of the bed height (original “swellographic” monitoring). The column described with gas pressurisation was tested with soft Sephadex G-10 and G-25. In spite of the reduction in external porosity there was no dramatic increase in back-pressure. The column proved to provide long-term stability of the packed bed and improvement in resolution. Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996  相似文献   
9.
Hydrogen bonding in crystalline N,N'-dialkylthioureas was examined with the help of single-crystal X-ray diffraction, DFT calculations, and Cambridge Structural Database (CSD) analysis. A CSD survey indicated that unlike the related urea derivatives, which persistently self-assemble into one-dimensional hydrogen-bonded chains, the analogous thioureas can form two different hydrogen-bonding motifs in the solid state: chains, structurally similar with those found in ureas, and dimers, that further associate into hydrogen-bonded layers. The formation of one motif or another can be manipulated by the bulkiness of the organic substituents on the thiourea group, which provides a clear example of steric control over the hydrogen bonding arrangement in crystalline organic solids.  相似文献   
10.
The crystal structure of a novel antimony(III) fluoride complex, ammonium undecafluorotriantimonate(III) (NH4)2Sb3F11, was determined. The crystals are triclinic: a = 7.780(2) Å, b = 8.370(2) Å, c = 10.620(1) Å, = 71.06(1)°, = 89.03(1)°, = 63.58(1)°, V = 579.1(2) Å3, Z = 2, (calcd) = 3.500 g/cm3, (exp) = 3.51 g/cm3, F(000) = 548.0, space group P . The structure consists of anionic [Sb3F11]2– chains and ammonium cations combined into a framework by the N–H···F hydrogen bonds.  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