首页 | 官方网站   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   459051篇
  免费   9568篇
  国内免费   3910篇
数理化   472529篇
  2021年   4557篇
  2020年   5264篇
  2019年   5548篇
  2018年   6709篇
  2017年   6505篇
  2016年   10037篇
  2015年   6698篇
  2014年   9992篇
  2013年   22110篇
  2012年   18125篇
  2011年   21820篇
  2010年   15070篇
  2009年   14936篇
  2008年   19293篇
  2007年   19111篇
  2006年   17651篇
  2005年   15703篇
  2004年   14386篇
  2003年   12622篇
  2002年   12420篇
  2001年   13930篇
  2000年   10598篇
  1999年   8541篇
  1998年   7120篇
  1997年   6750篇
  1996年   6204篇
  1995年   5799篇
  1994年   5721篇
  1993年   5446篇
  1992年   6049篇
  1991年   6095篇
  1990年   5782篇
  1989年   5545篇
  1988年   5527篇
  1987年   5419篇
  1986年   5096篇
  1985年   6585篇
  1984年   6685篇
  1983年   5283篇
  1982年   5359篇
  1981年   5336篇
  1980年   4888篇
  1979年   5317篇
  1978年   5454篇
  1977年   5364篇
  1976年   5313篇
  1975年   4900篇
  1974年   4870篇
  1973年   4858篇
  1972年   3444篇
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
1.
Journal of Radioanalytical and Nuclear Chemistry - Eco-friendly and low-cost composite, amidoxime-functionalized microcrystalline cellulose/mesoporous silica (MCC/MS-AO), were synthesized by...  相似文献   
2.
Journal of Experimental and Theoretical Physics - Dzyaloshinskii–Moriya interaction, DMI in short, represents an antisymmetric type of magnetic interactions that favor orthogonal orientation...  相似文献   
3.
Kinetics and Catalysis - A new ruthenium(II) cage complex with polar terminal groups in the apical substituents has been synthesized; the molecular design of the complex contributes to the...  相似文献   
4.
Lin  Yu  Wu  Yeyu  Tan  Xuecai  Wu  Jiawen  Huang  Kejing  Mi  Yan  Ou  Panpan  Wei  Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin...  相似文献   
5.
Russian Journal of General Chemistry - Aminophosphabetaines, i.e., isobutyl {[alkyl(dimethyl)ammonio]methyl}phosphonates with higher alkyl substituents at the nitrogen atom, were obtained by a...  相似文献   
6.
7.
8.
Journal of Structural Chemistry - The structures of Ni(II), Cu(II), and Zn(II) complexes with anions of 2,5-pyrrolyl-disubstituted nitronyl nitroxide (L1) and iminonitroxide (L2) diradicals (HL1 is...  相似文献   
9.
Mechanics of Composite Materials - Carbon fiber (CF)/ polyamide (PA6) composites are one of the most promising thermoplastic materials for automobile applications. However, the interfacial...  相似文献   
10.
In the pursuit to enlarge the library of polyimide materials for energy applications, new polyimide/MWCNTs composite films have been developed by MWCNTs-assisted polycondensation reaction of a hydroxyl and triphenylmethane-containing diamine with benzophenone tetracarboxylic dianhydride targeting to highlight their electrical storage capability as flexible electrodes in micro-supercapacitors (mSCs). The Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance, UV–vis, fluorescence, and Raman spectroscopies were used to demonstrate the evolution of interfacial interactions between MWCNTs and the precursors (diamine monomer and intermediate polyamidic acid) and polyimide matrix that proved to be the origin of MWCNTs homogeneous dispersion. Thus, composite films incorporating 1, 3, 5, and 10 w.t.% MWCNTs were obtained and thoroughly investigated with regard to their morphology, mechanical behavior, thermal stability, and electrical conductivity. The electrochemical performance of these composites was first analyzed in a classical three-electrode cell by cyclic voltammetry and galvanostatic charge-discharge in both aqueous and organic electrolyte systems. By far, the best electrical storage capacity was obtained with the composite polyimide film containing 10% MWCNTs that was further used as both active material and current collector in a flexible symmetric mSC realized by a straightforward and low-cost procedure. In the attempt to better exploit the advantages of this composite film, it was layered with a graphite-containing paint and tested as an electrode in a flexible mSC, which provided satisfactory results. To our knowledge, this is the first report on the electrical charge storage capability of a polyimide/MWCNTs free-standing film as a flexible electrode in mSCs, which do not require time- and resource-consuming processing steps.  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-23

京公网安备 11010802026262号