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   170篇
  免费   5篇
  国内免费   3篇
化学   85篇
力学   5篇
数学   35篇
物理学   53篇
  2023年   2篇
  2022年   4篇
  2021年   2篇
  2020年   6篇
  2019年   4篇
  2018年   5篇
  2017年   4篇
  2016年   9篇
  2015年   5篇
  2014年   8篇
  2013年   7篇
  2012年   9篇
  2011年   15篇
  2010年   10篇
  2009年   5篇
  2008年   16篇
  2007年   10篇
  2006年   12篇
  2005年   8篇
  2004年   1篇
  2003年   6篇
  2002年   8篇
  2001年   3篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   3篇
  1994年   2篇
  1992年   2篇
  1987年   1篇
  1985年   2篇
  1979年   1篇
  1973年   1篇
排序方式: 共有178条查询结果,搜索用时 15 毫秒
31.
32.
We give a simple geometric explanation for the similarity transformation mapping one-dimensional conformal mechanics to free-particle system. Namely, we show that this transformation corresponds to the inversion of the Klein model of Lobachevsky space (non-compact complex projective plane) . We also extend this picture to the N=2k superconformal mechanics described in terms of Lobachevsky superspace .  相似文献   
33.
A Ru-catalyzed direct thermal trifluoromethylation and perfluoroalkylation of N-acyloxazolidinones has been developed. The reaction is experimentally simple and requires inexpensive reagents while providing good yields of products with good levels of stereocontrol. Preliminary studies have shown notable compatibility with functional groups, aromatics, and certain heteroaromatic substituents. The described method provides a useful alternative for the synthesis of fluorinated materials in an experimentally convenient manner.  相似文献   
34.
We show how to construct the Perron–Bremermann function by using proper analytic disks. We apply this result to the polynomial hull of a compact set K defined on the boundary of the unit ball.  相似文献   
35.
We prove that the pluricomplex Green function has the product property for any domains and .

  相似文献   

36.
A convergent biomimetic synthesis of hemibrevetoxin B from d-glucal and d-arabinose utilizes an electrophile-promoted cascade anti-Baldwin cyclization of an epoxy alcohol. The epoxy alcohol arises from a palladium-catalyzed coupling of a highly functionalized organozinc compound and an alkenyl iodide, which serve as two chiral building blocks of similar size and complexity. This first successful implementation of a cascade epoxy alcohol cyclization for the synthesis of marine polycyclic ether toxins proceeds in 39 steps and 4% overall yield.  相似文献   
37.
38.
Substituted benzyl alkynyl ethers, prepared from the corresponding α-alkoxy ketones in a two-step sequence involving enol triflate formation and KOtBu-induced E2 elimination, undergo [3,3]-sigmatropic rearrangement/intramolecular 5-exo-dig cyclization at 60 °C to form substituted 2-indanones in good overall yields. 1,3-cis-Disubstituted-2-indanones are formed preferentially when the benzylic substituent R(1) is bulky. Substituted indenes may be prepared from 2-indanones in high yields by Horner-Wadsworth-Emmons reaction.  相似文献   
39.
New and effective methods for the synthesis of derivatives of pyrano[3,4-c][1,2,4]triazolo[4,3-a][1,5-a]pyridines were developed. Synthesized new tetracyclic heterocyclic systems containing pyrano[3,4-c]pyridine ring unknown in the literature were obtained for the first time. The rearrangement of Dimroth in the triazolo[4,3-a]pyridine systems for the first time was studied. The possibility of rearrangement of Dimroth in the new heterocyclic system has been investigated.  相似文献   
40.
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