全文获取类型
收费全文 | 254篇 |
免费 | 2篇 |
专业分类
化学 | 189篇 |
力学 | 5篇 |
数学 | 6篇 |
物理学 | 56篇 |
出版年
2020年 | 2篇 |
2014年 | 2篇 |
2013年 | 31篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 14篇 |
1983年 | 3篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1970年 | 1篇 |
1933年 | 2篇 |
1926年 | 2篇 |
1918年 | 1篇 |
1883年 | 1篇 |
1879年 | 1篇 |
1874年 | 2篇 |
1871年 | 1篇 |
1870年 | 4篇 |
排序方式: 共有256条查询结果,搜索用时 15 毫秒
1.
2.
Y. Guyot H. Loudyi S. Kazanskii J. C. Gcon C. Pdrini M. F. Joubert 《Radiation measurements》2004,38(4-6):753-757
Photoconductivity spectra of rare earth-doped insulating materials are measured using the resonant microwave cavity method. This technique is based on the detection of the cavity Q-factor changes induced by irradiation of the sample (inserted in the cavity) by a pulsed tunable laser. Results obtained with Lu2(SiO4)O:Ce3+ and BaF2:Eu2+ are presented and discussed. Photoionization thresholds at 400 nm (3.1 eV) and 310 nm (4.0 eV) are measured for Lu2(SiO4)O:Ce3+ and BaF2:Eu2+, respectively. 相似文献
3.
4.
Nicolas Gaillard Alain Guyot Jerome Claverie 《Journal of polymer science. Part A, Polymer chemistry》2003,41(5):684-698
Amphiphilic block copolymers of poly(acrylic acid‐b‐butyl acrylate) were prepared by reversible addition–fragmentation chain transfer polymerization in a one‐pot reaction. These copolymers were characterized by NMR, static and dynamic light scattering, tensiometry, and size exclusion chromatography. The aggregation characteristics of the copolymers corresponded to those theoretically predicted for a star micelle. In a butyl acrylate and methyl methacrylate emulsion polymerization, low amounts of these copolymers could stabilize latices with solid contents up to 50%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 684–698, 2003 相似文献
5.
6.
The reaction between dibutyltin dilaurate (DBTL) and chloro-4-hexene-2 (containing its isomer chloro-2-hexene-3) as a model compound for the allylic chlorine atom in poly(vinyl chloride) has been studied in dichlorobutane solution at 80°C. The reactions observed—elimination of HCl to give hexadiene and substitution of the laurate group to give hexenyl laurate—are believed to obey E2 and SN2 mechanisms through a common intermediate carbocation, with a rather low selectivity towards the substitution owing to the associated structure of the DBTL. The kinetics are complex because of the complex nature of the exchange reaction between DBTL and Bu2SnCl2. A reverse reaction between the hexenyl laurate and the organo-tin chloride is proposed to explain the limitation of the substitution reaction. 相似文献
7.
Abramowicz H Belusevic R Blondel A Blümer H Böckmann P Brummel HD Buchholz P Burkhardt H Debu P Duda J Dydak F Falkenburg B Fiedler M Geiges R Geweniger C Grant AL Guyot C Hagelberg R Hepp V Hughes EW Kampschulte B Keilwerth H Kleinknecht K Knobloch J Krasny M Królikowski J Kurz N Lipniacka A Merlo J Müller E Para A Perez P Perrier F Pollman D Ranjard F Renk B Schuller J Taureg H Tittel K Turlay R Vallage B Wachsmuth H Wotschack J 《Physical review letters》1986,57(3):298-301
8.
R. Spitz J. L. Lacombe A. Guyot 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2625-2640
The kinetics of propene polymerization in heptane slurry at 1–4 bars was studied with a catalytic system that consisted of a solid catalyst prepared by adsorption of TiCI4 on pure porous MgCl2 (by dehydrating MgCl2, 6 H2O with thionyl chloride) and a cocatalytic, heptanic solution of ethylbenzoate (BE) and triethylaluminium (TEA). At a temperature approaching 60°C/polymerization began immediately after the introduction of the monomer. The polymerization rate decreased continuously during the reaction. The loss in activity, however, was not due to a diffusional effect (e.g., blocking of the catalyst by the growing polymer). Studies of the ageing of the catalytic system showed a deactivation of the catalytic system itself as a function of the time of contact between the catalyst and the cocatalyst. The product of the thermal decomposition of the complex 1:2 formed by the reaction of BE with TEA was not associated with the deactivation process or stereospecific control, which depend on the BE/AI ratio and the presence of the complex. 相似文献
9.
Pyrolyses of acrylonitrile-methacrylic acid copolymers and their sodium salts were studied under inert atmosphere at various heating rates using thermogravimetric analysis coupled with gas liquid chromatography, thermal volatilization analysis, differential scanning calorimetry and flash pyrolysis coupled with GLC and eventually mass spectrometric analysis. The mechanisms of the nitrile oligomerization and subsequent chain scission, giving rise to volatilization, are discussed in connection with the sequence distribution of monomeric units in the copolymers. 相似文献
10.
Ta Chi Chiang Quang-Tho Pham Alain Guyot 《Journal of polymer science. Part A, Polymer chemistry》1977,15(9):2173-2191
Constant-composition copolymers of methyl methacrylate and vinylidene chloride produced by radical copolymerization are studied by 1H-NMR at 60 and 250 MHz. The different methods of the literature for the derivation of reactivity ratios from either the copolymer composition or the sequence average lengths, or even the diad distribution, are applied but lead to rather dispersed results. A new graphical method is proposed, based on the use of peculiar values of the triad distribution functions. It allows us to detect a penultimate effect for the vinylidene chloride-rich region. In the same range, a change in tacticity of the diads and triads on the methylmethacrylate sequences, as compared with homopolymers, is observed; it suggests that the anomaly is caused by the competition of the depropagation reaction. 相似文献