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181.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
182.
Guan-Yeow Yeap Wan-Sinn Yam Daisuke Takeuchi Kohtaro Osakada Ewa Gorecka Wan Ahmad Kamil Mahmood Peng-Lim Boey Shafida Abd Hamid 《Liquid crystals》2008,35(3):315-323
A series of new isoflavonic esters 7-decanoyloxy-3-(4'-substitutedphenyl)-4H-1-benzopyran-4-ones containing a heterocycle in their central core with one flexible alkyl chain and various substituents, R (where R = F, Cl, Br, CH3, OCH3, or H) at 4'-position at one end, have successfully been synthesised, isolated, and characterised. The physical properties of title compounds were studied using spectroscopic techniques (Fourier transform infrared, 1H and 13C nuclear magnetic resonance). The liquid crystalline properties and the textures of these compounds along with their thermal stabilities were investigated via polarising optical microscopy and differential scanning calorimetry. All the compounds except the member without the substituent were enantiotropic mesogens exhibiting smectic A and/or nematic phases. The layer periodicities in relation to different phases were substantiated by X-ray diffraction wherein the molecules within the SmA phase were found to be intercalated. The structural changes that resulted in a variation of transition temperature as well as the electronic polarisability of the respective compounds are also discussed. 相似文献
183.
The interaction of 3,5-carbonyl-substituted derivatives of 1,4-dihydropyridine and some analogs of it with hydrazine hydrate occurs with fission of the heterocycle. In the case of alkoxycarbonyl-substituted compounds a reverse Michael reaction predominates leading to fragmentation of the molecules. 相似文献
184.
Certain 2-phenylbenzothiazoles containing substituents on the benzothiazole ring possess important biological properties, yet the majority of synthetic methods to 2-phenylbenzothiazoles described to date focus on their unsubstituted ring counterparts. Here we describe a new concise and efficient synthetic route to biologically relevant 2-phenylbenzothiazoles in high yield from the reaction of substituted 2-aminothiophenol disulfides and benzaldehydes, promoted by the inexpensive and non-toxic inorganic oxidant sodium metabisulfite in DMSO at 120 °C. Our new method is tolerant of a range of substituents on both the benzothiazole and phenyl ring, and affords efficient access to substituted 2-phenylbenzothiazoles without the need for column chromatography. 相似文献
185.
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187.
《Journal of Coordination Chemistry》2012,65(13):2127-2159
AbstractThis review continues the previous articles (I. Haiduc, J. Coord. Chem., 71, 3139 (2018) and J. Coord. Chem., 72, 35 (2019)), which discussed the structures with nitrogen-donor species (atoms and molecules) acting as centers in inverse coordination complexes. i.e. metal compounds which display an arrangement of acceptor and donor sites opposite to that occurring in conventional coordination complexes. This review is Part 1 of a work which introduces the topology of inverse coordination complexes with organic nitrogen heterocycles, and presents a panorama of five-membered rings and covers pyrazole, imidazole, triazoles, tetrazole, pyrrole, oxadiazole, thiadiazole, azaphospholes, and smaller rings. 相似文献
188.
Consecutive Ring Expansion and Contraction for the Synthesis of 1‐Aryl Tetrahydroisoquinolines and Tetrahydrobenzazepines from Readily Available Heterocyclic Precursors
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Jessica E. Hill Dr. Johnathan V. Matlock Dr. Quentin Lefebvre Dr. Katie G. Cooper Prof. Jonathan Clayden 《Angewandte Chemie (International ed. in English)》2018,57(20):5788-5791
Tetrahydroisoquinolines and tetrahydrobenzazepines were prepared by acid‐promoted ring contraction of cyclic ureas, which were themselves formed by ring expansion of indolines and tetrahydroquinolines. The consequent overall one‐carbon insertion reaction gives these 6‐ and 7‐membered heterocyclic scaffolds in three steps from readily available precursors. Other ring sizes may be formed by an alternative elimination reaction of bicyclic structures. Scalability of the method was demonstrated by operating it in a flow system. 相似文献
189.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(5):599-603
In recent years, N‐heterocyclic carboxylate ligands have attracted much interest in the preparation of new coordination polymers since they contain N‐atom donors, as well as O‐atom donors, and have a rich variety of coordination modes which can lead to polymers with intriguing structures and interesting properties. A new two‐dimensional coordination polymer, namely poly[[μ3‐2,2′‐(1,2‐phenylene)bis(4‐carboxy‐1H‐imidazole‐5‐carboxylato)‐κ6O4,N3,N3′,O4′:O5:O5′]manganese(II)], [Mn(C16H8N4O8)]n or [Mn(H4Phbidc)]n, has been synthesized by the reaction of Mn(OAc)2·4H2O (OAc is acetate) with 2,2′‐(1,2‐phenylene)bis(1H‐imidazole‐4,5‐dicarboxylic acid) (H6Phbidc) under solvothermal conditions. In the polymer, each MnII ion is six‐coordinated by two N atoms from one H4Phbidc2− ligand and by four O atoms from three H4Phbidc2− ligands, forming a significantly distorted octahedral MnN2O4 coordination geometry. The MnII ions are linked by hexadentate H4Phbidc2− ligands, leading to a two‐dimensional structure parallel to the ac plane. In the crystal, adjacent layers are further connected by N—H…O hydrogen bonds, forming a three‐dimensional structure in the solid state. 相似文献
190.