全文获取类型
收费全文 | 164篇 |
免费 | 2篇 |
专业分类
化学 | 115篇 |
力学 | 9篇 |
数学 | 7篇 |
物理学 | 35篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 2篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
31.
Didier Gaude Raymond Le Goaller Jean-Louis Luche Jean-Louis Pierre 《Tetrahedron letters》1984,25(51):5897-5898
Polyethylene oxides are efficient phase transfer catalysts which promote the reduction of CC, CC bonds as well as aromatic substrates by the Na-k eutectic. Yields and general conditions of the reaction give it a generally useful synthetic value. 相似文献
32.
Jayne Carlos de Souza Barboza Christian Pétrier Jean-Louis Luche 《Tetrahedron letters》1985,26(7):829-830
Organozinc reagents, prepared by sonication from organic halides, lithium and zinc bromide, add conjugatively to α-enals in the presence of nickel acetylacetonate. Satisfactory yields are obtained from arylbromides. 相似文献
33.
Jocelyn Hung Dennis J. Mcnamara Leslie M. Werbel 《Journal of heterocyclic chemistry》1983,20(6):1575-1580
7-Chloro-3-(2,4-dichlorophenyl)-3,4-dihydro-1H-thioxanthene-1,9 (2H)-dione (10), and a variety of analogs and derivatives were prepared as sulfur isosteric analogs of the acridinedione antimalarial agent, floxacrine. The compounds were devoid of antimalarial activity against P. berghei in mice. 相似文献
34.
Polyethylene oxides are shown to promote an efficient dihalocarbene formation from bromo — and chloroform and solid potassium hydroxide — Adducts with olefins are obtained in High yields. 相似文献
35.
36.
A significant improvement in the Wittig-Horner synthesis of allenyl sulfones and allene carboxanilides is described under ultrasonic irradiation in a homogeneous phase. 相似文献
37.
Bruno A. Figadère J. Steven McElfresh Kent M. Daane Jocelyn G. Millar 《Tetrahedron letters》2007,48(48):8434-8437
Headspace volatiles of virgin female grape mealybugs contained a single compound that elicitited responses from antennae of males in GC-electroantennogram analyses. The structure, identified as (R∗,R∗)-trans-(3,4,5,5-tetramethylcyclopent-2-en-1-yl)methyl 2-methylpropanoate, an irregular, non-head-to-tail monoterpenoid, was confirmed by synthesis. 相似文献
38.
Darío M. González Nicole B. Cruz Loreto A. Hernández Jocelyn Oyarce Rosario Benavente Carolina Manzur 《Journal of polymer science. Part A, Polymer chemistry》2020,58(4):557-567
Two Bis-β-diketonate zinc (II) complexes were synthesized using 1-(thiophen-2-yl)butane-1,3-dione and 1-(thiophen-2-yl)-3-(thiophen-3-yl)propane-1,3-dione as ligands. By electropolymerization of their thiophenyl groups, the metallopolymers deposited on FTO electrodes were obtained. The main objective was to study the reactivity of these compounds as ROP catalysts for PLA synthesis, using directly the zinc complexes (homogeneous catalysis) and also the modified electrodes with metallopolymers (heterogeneous catalysis). The homogeneous catalysis studies allowed the optimization of the polymerization conditions, such as reaction time, catalyst concentration, and the use of benzyl alcohol as cocatalyst, as well as their influence on the conversion rate, average molecular weight and polydispersity of PLA, using rac-LA and L-LA as monomers. Also, the effect on tacticity and thermal properties were discussed. Finally, the ROP studies using immersed modified electrodes in the polymerization medium were carried out under optimized experimental conditions. These tests were positive for one of the studied compounds, reaching conversions of up to 67%. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 557–567 相似文献
39.
40.
Proton transfer from the photoacid 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid (HPTS) to water is studied in reverse micelles with ionic (AOT=sodium dioctyl sulfosuccinate) and non‐ionic (BRIJ‐30=polyoxyethylene(4)lauryl ether) surfactants. The dynamics are studied by probing the transient electronic absorption and transient vibrational absorption, both with sub‐picosecond resolution. The reverse micelle sizes range from approximately 1.6 to 5.5 nm in diameter. For both surfactants it is found that the rate of proton transfer decreases with decreasing reverse micelle size, regardless of surfactant. In addition, for AOT reverse micelles, a fraction of the photoacid molecules exhibit non‐radiative decay, preventing proton transfer. 相似文献