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131.
Charles E. McKenna Boris A. Kashemirov Mari Fujimolo 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Individual E/Z isomers of the C-methyl ester 1 of α-(hydroxyimino)phosphonoacetic acid (“troika acid”) were recently prepared as dicyclohexylammonium salts and found to be stable at neutral pH.1 On alkaline demethylation followed by pH adjustment to 6–7, E?1 and Z?1 stereospecifically undergo P-Cαand Cα-Cβ cleavage, respectively.1 Herein we report synthesis of the corresponding P-methyl ester from trimethyl phos-phonoacetate 2. The product was isolated as its bis-DCHA+ salt E-3, with stereochemistry assigned by NMR.2 相似文献
132.
Boris A. Kashemirov Mari Fujimoto-posner Charles E. McKenna 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract The (E-oxime of phosphonoglyoxylic acid, or (E-troika acid [(E)-l] undergoe: fragmentation leading to phosphorylation of the aqueous solvent at neutral pH and room temperature.[1] In contrast, the corresponding C-methyl ester (a-2 is stable under these mild conditions. Conversion of the unreactive (E)-2 to (E)-1 requires dewthylation a pH 13–14, generating the polyanion of (E-1, which becomes reactive on protonation.[1] 相似文献
133.
Boris I. Usachev Vyacheslav Ya. Sosnovskikh Mikhail A. Shafeev Gerd-Volker Röschenthaler 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1315-1319
Abstract Alkyl 2-mercaptophenyl ketones react with trifluoroacetic anhydride in the presence of triethylamine to give 2-(trifluoromethyl)-4H-thiochromen-4-ones, which are transformed into the corresponding pyrazoles by treatment with hydrazine hydrate and into 1,1-dioxides by oxidation with H2O2 in AcOH. 相似文献
134.
Boris Trofimov Nina Gusarova Lambert Brandsma 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):601-604
Abstract Generation of phosphide anions from phosphorus red or phosphine under the action of strong bases followed by their reactions with organyl halides, electrophilic alkenes and alkynes proves to be the most straightforward and well-controlled route to mono-, di- or triorganylphosphines or phosphine oxides of diverse structure. 相似文献
135.
Svetlana F. Malysheva Natal’ya A. Belogorlova Nina K. Gusarova Alexander V. Artem’ev Alexander I. Albanov Boris A. Trofimov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1688-1693
Abstract Red phosphorus reacts with allylbenzene in the superbase system KOH-DMSO (130°C, 3 h, Ar) to give a mixture of bis(1-methyl-2-phenylethyl)phosphane (1), bis(1-methyl-2-phenylethyl)phosphane oxide (2), and 1-methyl-2-phenylethylphosphinic acid (3). Secondary phosphane oxide 2 and phosphinic acid 3 have been isolated from this mixture in 35% and 32% yield, respectively. Microwave activation of the reaction (200 W, 30 min) affords secondary phosphane 1 as the main product in 48% yield. GRAPHICAL ABSTRACT 相似文献
136.
Polystyrene, cross-linked with 7.8% of divinylbenzene, formed a stable complex in chloroform with boron trifluoride containing 0.11% of boron, while cross-linked polystyrene-4-vinylpyridine resins containing 2–2.5% of pyridine rings formed a stable complex with boron trifluoride, containing 1.04% of boron. Both complexes catalyze conversions of aromatic aldehydes, ketones, and acids with alcohols into corresponding acetals, cyclic ketals, and esters; diphenylmethanol converts into ether. The structure of the alcohol plays an important role, with conversions decreasing in the order 1-butanol, 2-butanol, tert-butanol. Both complexes are very stable and in most cases more reactive than the cross-linked polystyrene-A1C13 complex. 相似文献
137.
Nina K. Gusarova Pavel A. Volkov Nina I. Ivanova Boris G. Sukhov Ludmila I. Larina Olga N. Kazheva Grigorii G. Alexandrov Oleg A. D’yachenko Boris A. Trofimov 《Tetrahedron letters》2013
The oxidative cross-coupling between 4-hydroxy-6-methyl-2-pyrone or 3-hydroxy-2-methyl-4-pyrone and secondary phosphine chalcogenides proceeds in CCl4/Et3N under mild conditions (20–52 °С, 0.75–10 h) through the hydroxyl group to give O-(6-methyl-2-oxo-2H-pyran-4-yl) diorganylphosphinochalcogenoates or O-(2-methyl-4-oxo-4H-pyran-3-yl) diorganylphosphinochalcogenoates, in high yields. 相似文献
138.
139.
140.
Boris Remenec Silvia Dulanská Ľubomír Mátel Ján Bilohuščin 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):117-122
The behaviour of 95Zr and 95Nb isotopes on TEVA® resin column was studied. The influence of hydrofluoric, hydrochloric, oxalic and sulphuric acids on the separation and chemical yield of zirconium and niobium was tested. The method is suitable for the separation of 93Zr and 94Nb isotopes from hydrofluoric, hydrochloric and sulphuric acid by using different concentrations of the acid for the load or elutes solutions. Samples from reactor and fuel assemblies such as the control-rod connection rod, shielding/absorber parts of fuel rods, neutron in-core measurement channels, pressure vessel basic construction material and internal cladding, core barrel and reactor protection tube unit were analysed. 相似文献