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91.
Masihul Hasan Mehdi Musawir Paul N. Davey Ivan V. Kozhevnikov 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):77-84
The liquid-phase oxidation of a series of saturated and unsaturated non-allylic alcohols to aldehydes with oxygen or air catalysed by tetra-n-propylammonium perruthenate (TPAP, represented as [(n-Pr)4N]RuO4) at 80–110 °C is shown to proceed with selectivities of 72–91% at 55–80% alcohol conversion. The unsaturated alcohols, such as 9-decenol, 9-octadecenol and β-citronellol, give the corresponding unsaturated aldehydes without competing double bond attack. The time course of oxidation indicates a complex reaction mechanism. The results on oxidation of a test alcohol, t-Bu(Ph)CHOH, suggest that one-electron processes do not play an important role in the TPAP-catalysed aerobic oxidation of alcohols. 相似文献
92.
V. A. Shaposhnik V. I. Vasil’eva R. B. Ugryumov M. S. Kozhevnikov 《Russian Journal of Electrochemistry》2006,42(5):531-537
A laser interferometry method is proposed for studying the instability of concentration fields during electrodialysis. It is shown that exceeding the limiting diffusion current density first gives rise to alternating oscillations and then to oscillations at the membrane whose ionogenic groups exhibit the lowest catalytic activity towards the water dissociation reaction. Thereafter, the auto-oscillation process extends over the whole solution volume in the compartments, and dissipative chaos is observed with a further increase in the current density. This instability is presumably a consequence of unevenly distributed heat sources, namely, the Joule heat and the heat of dissociation and recombination of water molecules. 相似文献
93.
I. V. Kozhevnikov V. E. Taraban'ko K. I. Matveev V. D. Vardanyan 《Reaction Kinetics and Catalysis Letters》1977,7(3):297-302
The catalytic acetoxylation of ethylene and propylene occurs under the action of oxygen in the presence of Pd(II)+HPA-6, where HPA-6 is the heteropolyacid H9PMo6V6O40. In addition to the products of acetoxylation (alkenyl and allyl acetates), oxidation products (acetaldehyde and acetone) are also formed. The selectivity of acetoxylation increases upon the addition of NaOAc.
— — Pd(II)+-6, -6 H9PMo6V6O40. (- ) — . NaOAc.相似文献
94.
I. V. Kozhevnikov A. I. Tsyganok M. N. Timofeeva S. M. Kulikov V. N. Sidelnikov 《Reaction Kinetics and Catalysis Letters》1992,46(1):17-23
Liquid-phase alkylation of p-tert-butylphenol (TBP) and p-cresol by olefins and benzyl chloride in the presence of solid heteropoly acids (HPA) H3PW12O40 and 25% H3PW12O40/SiO2 at 100–150°C provides high yields of mono- and disubstituted products. HPAs are more active than H2SO4, easily separated from the reaction mixture and can be used repeatedly. -- () - () H3PW12O40 25% H3PW12O40/SiO2 100–150°C - - . , H2SO4, - - . 相似文献
95.
By the oxidation of raesitylene by hydrogen peroxide in AcOH-Ac2O-H2SO4 one can obtain mesitol (2,4,6-trimethylphenol) (with a selectivity of 57–69% at a mesitylene conversion of 22–16% and the acetate of mesitol with a selectivity of 72–85% at 25–22% conversion. The peroxide responsible for the oxidation of mesitylene in this system is in the form of peracetic acid, formedin situ. Over the concentration range studied, the reaction is first order in AcOOH, mesitylene, and H2SO4. Hydroxylation of mesitylene by AcOOH proceeds by an electrophilic substitution mechanism, the limiting step being the formation of the -complex.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2716–2721, December, 1990.The authors express their thanks to L. V. Efremova, G. M. Maksimov, and V. D. Chinakov for their assistance in this work. 相似文献
96.
M.V. Patrakeev V.L. Kozhevnikov K.R. Poeppelmeier 《Journal of solid state chemistry》2005,178(3):921-927
Electrical conductivity, thermopower and oxygen content were measured for La1−xSrxFeO3−δ (x=0.2, 0.5, 0.9) within the oxygen partial pressure range 10−4-0.5 atm and at temperatures 750-950 °C. The dominating charge carriers under these experimental conditions are electron holes. The results of oxygen nonstoichiometry measurements are used to estimate the concentration of holes and to analyze data on conductivity and thermopower. The changes in thermopower are described by the model assuming that the number of sites accessible for migration of holes is independent on oxygen content. The mobility of electron holes is calculated, and it is found to be virtually independent on temperature in the compositions with x<0.5 while compositions with x>0.5 exhibit thermally activated mobility and mobility values about 0.1 cm2 V−1 s−1 or smaller. It is suggested that the main contribution to the composition dependent variations in electron hole mobility are associated with Coulomb interactions at small x's, whereas at high degrees of doping the mobility of holes is most strongly affected by the increasing amount of oxygen vacancies. 相似文献
97.
The linearized initial‐boundary value problem describing small motions of the viscous, barotropic compressible fluid in a bounded vessel is studied under various boundary conditions (Dirichlet, Neumann and intermediate). It is shown that the corresponding operator generates an analytic semigroup in the space L2. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
98.
The phase of φω interference in the reaction e + e ? → π+π?π0 near the energy of the φ(1020) peak is calculated within an approach that is virtually independent of the model for φω mixing. A comparison with the phase measured recently (with a poor precision) shows that the deviation of the measured result from the expected value of 180° is associated largely with the effect of the right shoulder of the ω(782) peak in the region of the φ(1020) peak. The ω width at the energy equal to the φ mass is within the interval 120–200 MeV. The effect of the φω-state-induced unitarity corrections to the φ and ω coupling constants on the phase of ρπ interference is considered in detail. 相似文献
99.
100.
V. N. Kozhevnikov D. N. Kozhevnikov V. L. Rusinov O. N. Chupakhin 《Chemistry of Heterocyclic Compounds》1999,35(4):470-473
Reaction of 6-aryl-3-dimethylamino-1,2,4-triazine 4-oxides with KCN results in constriction of the heterocycle and formation
of 3-amino-5-aryl-4-nitrosopyrazoles. Several methods including labelled K13C15N are used to demonstrate that the reaction proceeds through the ANRORC mechanism.
Dedicated to Professor Henk van der Plas on his 70th birthday.
For No. 2, see [1].
Urals State Technical University, Ekaterinburg 620002, Russia; e-mail: mike@htf.ustu.ru. Translated from Khimiya Geterotsiklicheskikh
Soedinenii, No. 4, pp. 532–535, April, 1999. 相似文献