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   76篇
  免费   0篇
化学   58篇
力学   1篇
数学   10篇
物理学   7篇
  2013年   4篇
  2012年   2篇
  2011年   1篇
  2010年   1篇
  2009年   3篇
  2008年   6篇
  2007年   4篇
  2006年   4篇
  2005年   2篇
  2004年   1篇
  2003年   4篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1992年   4篇
  1991年   6篇
  1990年   8篇
  1989年   2篇
  1988年   1篇
  1987年   6篇
  1986年   2篇
  1984年   1篇
  1974年   1篇
  1969年   1篇
排序方式: 共有76条查询结果,搜索用时 15 毫秒
21.
22.
P-Phenyl-C,C-bis(trimethylsilylthio)methylenephosphine is hydroborated with dicyclohexylborane, with the hydroboration product undergoing spontaneous elimination with the formation of trimethylsilylthio(dicyclohexyl)borane and P-phenyl-C-trimethylsilylthiomethylenephosphine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2127–2129, September, 1990.  相似文献   
23.
The nature of the dialkylamino group has a significant effect on the reactivity of C-(N,N-di-alkylamino)phosphaalkenes upon their reaction with sulfur.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1169–1172, May, 1990.  相似文献   
24.
PhSCl adds regiospecifically to the P=C double bond in C-(N,N-dimethylamino)-methylene-P-phenylphosphine to give PhP(SPh)2 and Cl2CHNMe2.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 948–949, April, 1991.  相似文献   
25.
Prior bounds expressing stability in the right-hand side are constructed for difference schemes approximating the heat equation with nonlocal boundary conditions. The constraints on the grid increment guaranteeing stability in the right-hand side are identical with the previously established criteria for stability in initial values. __________ Translated from Prikladnaya Matematika i Informatika, No. 23, pp. 134–139, 2006.  相似文献   
26.
Conclusions Unstable methylenephenylphosphine may be trapped by dialkylborane. The hydroborylation reaction proceeds with the formation of a product with a P-H bond.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1674–1676, July, 1989.  相似文献   
27.
Conclusions Treatment of phenylbis(hydroxymethyl)phosphine sulfide with acetals and ketals gives the corresponding 2-substituted and 2,2-disubstituted 5-phenyl-5-thio-1,3,5-dioxaphosphorinanes in which the P-Phenyl substituent occupies an axial position.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 418–422, February, 1987.  相似文献   
28.
Intramolecular charge separation from the second singlet excited state of directly linked Zn-porphyrin-imide dyads and following charge recombination into the first singlet excited state has been investigated in the framework of a model involving three electronic states (the first and the second singlet excited and charge separated states) as well as their vibrational sublevels. Kinetics of the transitions between these states are described in terms of the stochastic point-transition approach. The influence of the model parameters (free energy change of charge separation, magnitude of the reorganization energies of the medium and the high frequency intramolecular vibrations, the rate of relaxation of the medium and the intramolecular high frequency vibrational mode) on the kinetics of population of both the charge separated and the first singlet excited states has been explored. Simulations of the kinetics of the charge separated state population have allowed reproducing the distinctive features of the kinetics observed in the experiment [Wallin, S.; Monnereau, C.; Blart, E.; Gankou, J.-R.; Odobel, F.; Hammarstr?m, L. J. Phys. Chem. A 2010, 114, 1709]: (i) two maxima on short time scale (hundreds of femtoseconds) and long time scale (tens of picoseconds), (ii) the magnitudes of both maxima, and (iii) the depth of the notch between the maxima.  相似文献   
29.
1,2‐Bis[bis(trimethylsilyl)methylchlorophosphino]ethane was prepared by the reaction of 1,2‐bis(dichlorophosphino)ethane and the Grignard reagent of bis(trimethylsilyl)chloromethane. It adds DBN (1,5‐diazabicyclo[4.3.0]non‐5‐ene) in a 1:2 ratio. Subsequent treatment with t‐BuLi converts the adduct to a condensation product, which in its enamine form reacts with MgCl2 (still present from the preparation of 1 ) to give the cyclic magnesium diamide 2 . By additional coordination of the two phosphine sites of the condensation product, 2 attains a tricyclic structure. An unchanged DBN molecule completes the pentacoordination of the magnesium atom. The structure of product 2 has been determined by single crystal X‐ray diffraction. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:197–199, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10122  相似文献   
30.
The potential energy hypersurface of the conversion of aminophosphaethyne ( 1 ) to 1-aza-3-phosphaallene ( 2 ) has been studied with the MNDO method. The interconversion includes five intermediate species. The structure and energy of 1 and its isomers produced by a hydrogen shift have been calculated also with ab initio molecular orbital theory by a split valence basis set including a polarization function at the P atom. The results reveal that all the isomers are equilibrium structures. The ab initio calculation predicts the carbenaazaphosphirane 3 to be the intermediate lowest in energy. It is suggested that a carbene ( 3 ), phosphinidene ( 4 ) or azaphosphirene ( 5 ) are responsible for the 1-aza-2,4-diphosphole formation.  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