全文获取类型
收费全文 | 86篇 |
免费 | 1篇 |
专业分类
化学 | 62篇 |
数学 | 12篇 |
物理学 | 13篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
2.
A vinyl bis-sulfone Michael type approach towards heteroatom vinylation was applied on nitrogen derivatives. Cyclic thionocarbamates--mainly 1,3-oxazolidine-2-thiones--were converted into their N-vinyl counterparts; the procedure proved particularly efficient in the case of carbohydrate-derived complex structures. 相似文献
3.
FitzGerald PA Carr MW Davey TW Serelis AK Such CH Warr GG 《Journal of colloid and interface science》2004,275(2):649-658
Dimeric poly(ethylene oxide) surfactants (or nonionic gemini surfactants) with the structure (Cn-2H2n-3CHCH2O(CH2CH2O)mH)2(CH2)6 (or GemnEm), where n is the alkyl length and m is the average number of ethylene oxides per head group, were synthesized. Surfactants were synthesized with alkyl chain lengths n = 12, 14, and 20 and m = 5, 10, 15, 20, and 30. Water solubilities and cloud temperatures at 1 wt% were determined by measuring turbidity as a function of temperature. Cloud temperatures increase with m and decrease with n, as observed for conventional surfactants. For large m the cloud temperatures were all above 100 degrees C. Surfactants with small m (i.e., n = 12, 14, m = 5 and n = 20, m = 10) were insoluble at room temperature, forming two-phase mixtures. Critical micelle concentrations (CMCs) were measured using a pyrene fluorescence method and are all in the range of 10(-7) to 10(-6) M, with the lowest values from the surfactants with large n and small m. CMCs of mixtures with both anionic and nonionic conventional (monomeric) surfactants were well described by an ideal mixing model. 相似文献
4.
Sigitas Tumkevicius Linas LabanauskasVirginija Bucinskaite Algirdas BrukstusGintaras Urbelis 《Tetrahedron letters》2003,44(35):6635-6638
(1-Amino-1H-benzimidazol-2-yl)methanol 1 with thionyl chloride at reflux afforded 3-chlorobenzimidazo[1,2-c][1,2,3]thiadiazole 4, which reacted with various nucleophiles to give different products depending on the nature of the solvent. The structures of 4 and di(benzimidazo[1,2-c][1,2,3]thiadiazol-3-yl)sulfide 8 were confirmed by single-crystal X-ray analysis. 相似文献
5.
Neringa Kleizien? Virgin? Amankavi?ien? Ulf Berg Carsten Schicktanz Klaus Schlothauer Algirdas ?a?kus 《Monatshefte für Chemie / Chemical Monthly》2006,43(9):1109-1117
Condensation of 1-substituted 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones with 5-nitrosalicylaldehyde afforded 1′-[(N-monosubstituted carbamoyl)methyl]indoline nitrospirobenzopyrans.
Treatment of the latter with strong base led to the formation of a mixture of cis/trans-5a,13-methano-1,3-benzoxazepino[3,2-a]indoles. Results of semiempirical calculations gave evidence that such a transformation of nitrospirobenzopyrans to bicyclic
indole derivatives could proceed via a single transition state, where the negatively charged carbon atom attacks the vinylic double bond of the spiropyran system. 相似文献
6.
7.
8.
Regina Janciene Zita Stumbreviciute Ausra Vektariene Lidija Kosychova Romualdas Sirutkaitis Algirdas Palaima Zita Staniulyte Benedikta D. Puodziunaite 《Heteroatom Chemistry》2008,19(1):72-81
A number of 1‐substituted 4H,5H,6H‐[1,3]thiazolo[3,2‐a][1,5]benzodiazepinium‐11‐bromides and S‐(2‐oxo‐2‐phenyl‐X‐(p)‐ethyl)‐3‐(2‐methyl‐1H‐benzimidazol‐1‐yl) propane (or butane) thioate hydrobromides were obtained by direct reaction of the 5‐acetyl(or formyl, or anilinocarbonyl)‐substituted tetrahydro‐1,5‐benzodiazepine‐2‐thiones with aromatic α‐bromoketones. 2‐[(1‐Acetyl‐2(or 3)‐methyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepin‐4‐yl) sulfanyl]‐1‐phenylethanones as intermediates of the formation of thiazolo [3,2‐a][1,5]benzodiazepine and N‐substituted 2‐methyl‐1H‐benzimidazole derivatives have been synthesized. Semiempirical AM1 calculations of a mechanism and energetic parameters for the heptatomic nucleus rearrangement to benzimidazole ring are presented. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:72–81, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20414 相似文献
9.
Jolanta Rousseau Vilija Kriščiūnienė Ilona Rimkevičiūtė Cyril Rousseau Virginė Amankavičienė Algirdas Šačkus Arnaud Tatibouët Patrick Rollin 《Monatshefte für Chemie / Chemical Monthly》2009,140(3):339-348
Abstract Modular conditions for the formation of thioureas or pyrimidine-4-one-2-thiones connected to the benzo[b]thiophene, benzene and indole structures were performed. A benzo[b]thiophene isothiocyanate derivative was used as a model to study the condensation with simple aromatic amines and amino-l-sorbose derivative. The construction of pyrimidine-4-one-2-thiones using basic conditions afforded efficiently new heterocyclic
aromatics, which were further transformed using the alkylated sulfur as a leaving group in palladium-catalyzed cross-coupling
reactions.
Graphical abstract
相似文献
10.
Algirdas Matijoška Tatjana Charkova Zenonas Kuodis Vladislava Voiciuk Olegas Eicher-Lorka 《Central European Journal of Chemistry》2012,10(1):113-120
The synthesis of a new halogenide containing hexyltriethylene glycol chain functionalized with biotin is reported. The general
possibility of this linker to use as the building block for biotinylated compounds syntheses is demonstrated. Two biotinylated
esters with different properties for useful surface modification and as fluorescence probes for proteins marking were synthesized.
The properties of mentioned compounds were investigated by using surface plazmon resonance ellypsometry and fluorescence spectroscopy. 相似文献