全文获取类型
收费全文 | 253篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
化学 | 180篇 |
力学 | 1篇 |
数学 | 12篇 |
物理学 | 74篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 13篇 |
2010年 | 3篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 16篇 |
2006年 | 16篇 |
2005年 | 15篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 14篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1978年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有267条查询结果,搜索用时 31 毫秒
1.
I. Antoniou M. Gadella J. Mateo G.P. Pronko 《International Journal of Theoretical Physics》2003,42(10):2389-2402
Through two examples: the Friedrichs model and a particular case of central potential scattering, we illustrate the way of constructing Gamow vectors. 相似文献
2.
Soderstrom E McKenna JA Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R 《Physical review letters》1990,64(25):2980-2983
3.
Komamiya S Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gatto C Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R 《Physical review letters》1990,64(24):2881-2884
4.
5.
6.
F. Catalina C. Peinado E. L. Madruga R. Sastre J. L. Mateo N. S. Allen 《Journal of polymer science. Part A, Polymer chemistry》1990,28(5):967-972
A novel monomer, 2-acryloyl thioxanthone (TXA), was prepared by reaction of 2-hydroxy thioxanthone with acryloyl chloride. Copolymerization of TXA with methyl methacrylate (MMA) in DMF at 80°C was studied in order to evaluate relative reactivities of these monomers. Values of 1.36 and 0.5 were found for the respective reactivity ratios of MMA and TXA, respectively. The resonance stabilization and polar properties were determined and discussed in terms of spectroscopic data. 相似文献
7.
Reaction conditions and structure of the starting enamines (cyclic or open-chain) determine greatly the final products of the title reactions. Whereas in benzene and acetonitrile, DMAD and 1 give a mixture of the diastereoisomeric dienamines 5, in methanol they afford pirrolizine 3. Enaminofuranones 2 and 10 furnish the corresponding “Michael adducts” 7a,b,c and 11a,b,c but fail to yield pirrolizines. It has been demonstrated that above b and c adducts differ exclusively on the arrangement of groups around a chiral axis. 相似文献
8.
A new family of polyoxygenated stilbenophanes has been synthesized as conformationally restricted analogues of antimitotic combretastatins. By means of the McMurry olefination process, compounds derived from diethyleneglycol and 1,6-hexanediol were obtained, whereas Grubbs' catalyst failed in producing the ring-closing metathesis to this kind of macrocyclic products. 相似文献
9.
C. Alvarez-Ibarra E. Dvila A. Mateo P. Ortiz M. L. Quiroga 《Tetrahedron letters》1987,28(52):6667-6670
We report a new synthesis of thiazoles from a cyclocondensation reaction between dimethyl N-(ethoxycarbonylmethyl)iminodithiocarbonate (EMIC), carbon disulfide and alkylation of intermediate thiazole-2-thiolate with alkyl halides. 相似文献
10.
Azeto[1,2-a]imidazoles are prepared by a formal intramolecular [2+2] cycloaddition of imino-ketenimines in which an ethylene chain is linking the nitrogen atoms of both functionalities, bearing a methyl and a phenyl group on the terminal carbon atom of the heterocumulene. By acid-catalyzed hydrolysis these azeto[1,2-a]imidazoles are converted into 6,6,7-trisubstituted hexahydro-1,4-diazepin-5-ones, which have been alternatively prepared via intramolecular transamidation of N-(2-aminoethyl)-β-lactams. 相似文献