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   384篇
  免费   30篇
  国内免费   5篇
化学   321篇
力学   5篇
数学   30篇
物理学   63篇
  2023年   5篇
  2022年   13篇
  2021年   16篇
  2020年   29篇
  2019年   33篇
  2018年   31篇
  2017年   29篇
  2016年   36篇
  2015年   22篇
  2014年   30篇
  2013年   45篇
  2012年   20篇
  2011年   18篇
  2010年   14篇
  2009年   8篇
  2008年   18篇
  2007年   17篇
  2006年   9篇
  2005年   2篇
  2004年   5篇
  2003年   5篇
  2002年   6篇
  2001年   2篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1987年   1篇
  1985年   1篇
排序方式: 共有419条查询结果,搜索用时 109 毫秒
91.
92.
A simple convenient procedure for dehydration of aldoximes has been developed using silica gel/thionyl chloride in heterogeneous conditions. The method has been found to be effective for a wide range of aromatic oximes.  相似文献   
93.
Journal of Thermal Analysis and Calorimetry - In the present work, different passive methods have been numerically investigated to improve the thermal performance in a miniature channel. The heat...  相似文献   
94.
95.
A novel class of 3,4-dihydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones was synthesized in very short reaction times with good yields in the presence of 3-butyl-1-methyl imidazolium bromide as a room temperature ionic liquid at 120°C. The ionic liquid can be recycled for subsequent reactions without any loss of efficiency.  相似文献   
96.
97.
Using DFT methods, the electronic properties and the first hyperpolarizabilities of porphyrin‐like porous C24N24 fullerene decorated with (Li3O)n = (1–5) have been systematically investigated. It is found that Li3O molecules can effectively be adsorbed over N4 cavities of C24N24 with high interaction energies. This interaction is found to narrow the HOMO‐LUMO gap and work function values of C24N24. Thus its electronic properties are strongly sensitive to interaction with the Li3O molecules. Indeed, compared with the sole parent C24N24 fullerene, (Li3O)n = (1–5)@C24N24 possess large first hyperpolarizabilities (β0 ). Obviously, the Li3O superalkali chemisorbed over C24N24 fullerene exhibit not only excellent stability but also large first hyperpolarizability. Therefore, they are expected to be potential innovative candidates for excellent electro‐optical materials.  相似文献   
98.
This note makes a correction to the paper “Top local cohomology modules and Gorenstein injectivity with respect to a semidualizing module”.  相似文献   
99.
Herein, Ni(II) immobilized on modified mesoporous silica MCM-41 was designed and synthesized via a facile sequential strategy. The structure of the catalyst was characterized by X-ray diffraction. The thermal property of the as-synthesized materials was studied using thermogravimetric-differential thermal analysis. The average particles size and morphology of MCM-41@XA@Ni(II) were investigated using scanning electron microscopy and transmission electron microscopy. This nanostructure catalyst was effective for the selective oxidation of sulfides and acetylation of alcohols in solvent-free conditions. The easy recyclability of the catalyst and their complete chemoselectivity toward the sulfur group of substrates in the oxidation of sulfides are important “green” attributes of this catalyst.  相似文献   
100.
Journal of Radioanalytical and Nuclear Chemistry - Radiocolloides are essential for the detection of metastatic lymph nodes in breast cancer. In this study [67Ga]Ga-phytate, as an long-lived...  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