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31.
Ping He 《Journal of fluorine chemistry》2005,126(1):113-120
The reactions of fluoroalkanesulfonyl azides RfSO2N31 with N-alkylindoles 2 have been studied in detail. It was found that both solvent and the amount of the azides seriously affected the product distribution. 1 reacted with equimolar of 2 in ether or 1,4-dioxane affording 2-(N-substituted-indolinylidene)fluoroalkane sulfonylimines 3 as major product; While, treatment of 2 with 2 equiv. of 1 in ethanol, an unexpected product N-substituted-2-fluoroalkanesulfonimino-3-diazo-indolines 4 were obtained in good yield. The reaction mechanism was discussed. 相似文献
32.
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34.
Structures and energetics of reactants, transition states and cycloadducts of cycloadditions of nitrone with three-fluorinated dipolarophiles have been investigated with the density functional theory method B3LYP/6-31G*. Analysis of the results on the different reaction pathways shows that the reaction takes place along a concerted mechanism and proceeds more or less synchronously. The FMO analysis shows a strong HOMOdipole-LUMOdipolarophile interaction as the principal reason for the reactivity in these 1,3-dipolar cycloaddition reactions. Regioselectivity of the products of the reaction is predicted reliably by our calculations, the results provide a good prediction of the relatives rates observed experimentally as the dipolarophiles are varied. 相似文献
35.
Acyclic nitrones react with dimethyl acetylenedicarboxylate (DMAD) to give stable isoxazolines, from which the ones that contain electron-donating aromatic rings at the C3 position (R1) were shown to undergo unprecedented fragmentation at room temperature, giving the R1-aldehyde and inseparable product mixtures, probably due to the formation of highly reactive species such as iminocarbenes. Attempts to convert the isoxazolines to the corresponding stable azomethine ylides, by refluxing in toluene, again led to the same product mixtures as above (e.g., the room temperature decomposition). Isoxazolines when reacted with methoxide at room temperature afforded highly functionalised diastereomeric mixtures. Also, isoxazolines, when reacted with propylamine, gave the corresponding amides regioselectively, all of which were more stable than the parent isoxazolines. 相似文献
36.
2-Azido-3,5-dichloropyridine and 2-azido-5-chloro-3-fluoropyridine were given by reaction of sodium azide with 2,3,5-trichloropyridine, 3,5-dichloro-2-fluoropyridine or 5-chloro-2,3-difluoropyridine in ionic liquids. 1,3-Dipolar cycloaddition of 2-azido-3,5-dichloropyridine or 2-azido-5-chloro-3-fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5-trisubstituted [1,2,3]-triazoles in good yields and regioselectivities. 相似文献
37.
The 1,3-dipolar cycloaddition reactions of α-2-methoxyaryl nitrones with nitrostyrenes and chalcones have been investigated. The regiochemistry and stereochemistry of the resultant cycloadducts have been determined with the help of NMR spectroscopy and X-ray analysis. β-Nitrostyrenes add to nitrones to give two geometrical isomers, while the β-methyl-β-nitrostyrene gives a single isomer in relatively low yield. The chalcones give a single cycloadduct upon 1,3-dipolar addition. 相似文献
38.
A. M. Kibardin A. Kh. Plyamovatyi R. R. Shagidullin Yu. Ya. Efremov T. V. Gryaznova A. N. Pudovik 《Russian Chemical Bulletin》1994,43(2):283-285
The reaction of 1,3-dibutyl-2-ethoxy-4,5-dimethyl-2-oxo-1,3,2-diazaphosphol-4-ene with tetracyanoethylene gives 6-amino-1,3-dibutyl-5-cyano-2-ethoxy-4-(1-imino-2-cyanoethyl)-2-oxo-1,3,2-diazaphosphindane.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 303–305, February, 1994. 相似文献
39.
Published information on methods for the production of benzazetines and their dehydro derivatives (benzazetes) and their chemical
transformations is reviewed and analyzed. It was noted that benzazetines with an unsubstituted NH group are unstable and their
stable representatives have only became accessible in recent years. The tendency of benzazetines to undergo opening of the
four-membered heterocycle and isomerization processes was demonstrated. The wide-ranging synthetic possibilities of benzazetines
and benzazetes are indicated.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1763–1783, December, 2007. 相似文献
40.
Peter LeemingColin A Ray Stephen J SimpsonTimothy W Wallace Richard A Ward 《Tetrahedron》2003,59(3):341-352
Heterodiene [4π+2π] cycloadditions of (S,S)-4,5-diaryl-2-methylene-1,3-dioxolanes 1 to a series of β-amido-α,β-unsaturated carbonyl compounds are diastereoselective (d.r.≥4:1). The products can be purified by trituration or crystallisation and hydrolysed with acid to generate the corresponding β-amido carbonyl compounds, the overall sequence effecting an auxiliary-based enantioselective conjugate addition of an acetate enolate, leading to β-aminoacid derivatives. 相似文献