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91.
Selective reactions on a functional group of polyhydroxy compounds are extremelyuseful in organic synthesis, especially in the field of carbohydrate and nucleosidechemistry. Indirect methods for the selective reaction on a functional group ofpolyhydroxy compounds involve the use of protective groups. In order to utilize thismethodology efficiently, selective protection and deprotection of ceftain hydroxy groupswithin the polyhydroxy compound are required.Ketal formation is most commonly used f… 相似文献
92.
Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize α‐keto acetals directly. Using O2 as oxidant and alcohol as solvent and alkoxylation reagent, the reaction is practical from industrial viewpoint. Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn‐elimination regenerating the catalytically active organoselenium species. 相似文献
93.
《Tetrahedron letters》2014,55(52):7167-7171
Transprotection of acetals to bis(methoxyphenyl)methyl (BMPM) ethers can be efficiently achieved in the presence of copper dibromide as catalyst in acetonitrile at room temperature. Acetals are conveniently and selectively converted to the corresponding mono-protected diol with bis(methoxyphenyl)methyl isopropyl ether (BMPMOiPr) as the reagent. This new practical reagent allows the BMPM transfer to 1,3-dioxolanes or 1,3-dioxanes under copper catalysis. The reaction conditions are also very mild and tolerant to various functional groups, including other protecting groups. 相似文献
94.
Ramin Ghorbani-Vaghei Ardeshir Khazaei 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1169-1173
N-Bromobis(p-toluenesulfonyl)amine (NBBTA) is a novel and efficient reagent for the conversion of oximes to their corresponding carbonyl compounds in good yields under mild conditions. 相似文献
95.
A practical protocol for rapid and scalable synthesis of monofunctionalized α,ω-diols using a simple and inexpensive THP ether protection/deprotection strategy was described. Use of inexpensive DHP source and ease to remove excess water-soluble α,ω-diols and THP ether after deprotection render the process scale-friendly without need of column chromatographic separation. The application of present method was also illustrated in the preparation of heterobifunctional diols and well-defined extended oligo(ethylene glycol). 相似文献
96.
97.
Trinitratocerium(IV) bromate (TNCB) can be used as an efficient reagent for oxidation of alcohols and deprotection and oxidative deprotection of trimethylsilyl ethers under solvent‐free conditions. 相似文献
98.
David M. Casper 《合成通讯》2013,43(20):3501-3507
N‐tert‐Butyldecahydro‐3‐isoquinoline carboxamide (1) is a key structural fragment present in a variety of medicinally important HIV protease inhibitors. Derivatives of this carboxamide were prepared by alkylation with either 2‐iodoethanol, allyl bromide, or bromoacetaldehyde dimethylacetal. The corresponding aldehyde of the dimethylacetal derivative was prepared by reaction with BBr3 in CH2Cl2. 相似文献
99.
Rahman Hosseinzadeh Mahmood Tajbakhsh Farhad Ramzanian-Lehmali Marzieh Sadatshahabi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2279-2283
Deprotection of trimethylsilyl ethers to their parent aldehydes and ketones in high yields has been carried out using 2,6-dicarboxypyridinium fluorochromate under mild conditions. 相似文献
100.
The tentative identification of the reactive species in the condensation of Cp2 TiCl2 with salts of diacids to form titanium polysters is made. The reactive species are believed to be the same for both aqueous solution and interfacial systems, i.e., R -CO2 ? and Cp2 Ti2+ with reaction occurring in the aqueous phase. The condensation of Cp2 TiCl2 with disodium terephthalate in interfacial systems occurs via a pseudo-first-order reaction: Rate = K[Cp2 TiCl2] The rate-determining step (s) is believed to be diffusion of CP2 TiCl2 into the aqueous layer and/or hydrolysis of Cp2 TiCl2 相似文献