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   119篇
  免费   2篇
化学   92篇
力学   1篇
数学   18篇
物理学   7篇
无线电   3篇
  2023年   5篇
  2022年   7篇
  2021年   6篇
  2020年   8篇
  2019年   10篇
  2018年   8篇
  2017年   5篇
  2016年   4篇
  2015年   4篇
  2014年   1篇
  2013年   6篇
  2012年   6篇
  2011年   5篇
  2010年   7篇
  2009年   5篇
  2008年   6篇
  2007年   3篇
  2006年   2篇
  2005年   3篇
  2004年   5篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  1999年   3篇
  1995年   1篇
  1993年   1篇
  1988年   1篇
  1975年   1篇
  1967年   1篇
  1959年   1篇
排序方式: 共有121条查询结果,搜索用时 15 毫秒
1.
Electrospun nonwovens of poly(L-lactide) (PLLA) modified with multiwall carbon nanotubes (MWCNT) and linear ladder-like poly(silsesquioxane) with methoxycarbonyl side groups (LPSQ-COOMe) were obtained. MWCNT and LPSQ-COOMe were added to the polymer solution before the electrospinning. In addition, nonwovens of PLLA grafted to modified MWCNT were electrospun. All modified nonwovens exhibited higher tensile strength than the neat PLA nonwoven. The addition of 10 wt.% of LPSQ-COOMe and 0.1 wt.% of MWCNT to PLLA increased the tensile strength of the nonwovens 2.4 times, improving also the elongation at the maximum stress.  相似文献   
2.
Chlorine-containing polyfluorinated anilines and meta-phenylenediamines undergo selective hydrodechlorination easily upon reduction by zinc in aqueous ammonia. A new approach is thus provided to synthetically valuable, partially fluorinated arylamines based on utilizing polyfluorochloroarenes, which are available as intermediates of perfluoroarene production from perchloroarenes. When chlorine atoms are present in positions both ortho and para to the amino group, para chlorine is initially eliminated. Based on this reaction, a one-pot synthesis of partially fluorinated 4-aminopyridines from 3,5-dichlorotrifluoro- and 3-chlorotetrafluoropyridine has been realized.  相似文献   
3.
4.
5.
6.
Cu-catalyzed 1,3-dipolar cycloaddition of methyl 2-azidoacetate to iodobuta-1,3-diynes and subsequent Suzuki-Miyaura cross-coupling were used to synthesize new triazoles derivatives: 5-aryl-4-arylethynyl-1H-1,2,3-triazoles. Investigation of their optical properties by using UV absorption and fluorescence emission spectroscopies revealed that all molecules possess fluorescence properties with the values of the Stokes shift more than 100 nm. The photophysical behavior of the two most promising triazoles in polar and non-polar solvents was also studied.  相似文献   
7.
8.
The influence of the initial wood species and polymolecular characteristics on the characteristics of the surface of solid-phase lignin was estimated, and the correlation of these parameters with the ability of kraft lignins to stabilize the oleic acid-water emulsion was examined. The kinetics of breakdown of emulsions stabilized with kraft lignin was studied.  相似文献   
9.
System of sensors operating on the piezoquartz microweighing principle was employed to forecast the storage life of food products based on milk serum. Signals from the sensors are integrated into an output signal forming a recognizable “visual pattern” of an odor.  相似文献   
10.
The effect of low-molecular-weight electrolyte additions on the behavior of sulfate lignins in aqueous media was studied by capillary viscometry, tensiometry, and dynamic light scattering.  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