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排序方式: 共有465条查询结果,搜索用时 187 毫秒
1.
V. A. Petrosyan 《Russian Chemical Bulletin》1995,44(8):1353-1364
The results of studies on electrosynthesis involving carb- and heteroanions generated by cathodic deprotonation of acids (CDA), carried out in the laboratory headed by the author, are surveyed. These studies resulted in the elaboration of efficient electrochemical versions of the known Michaelis-Becker, Wittig-Horner, and Perkin reactions; electrochemical analogs of homolytic aromatic substitution, alkylation, heterocyclization,etc. were developed. Based on CDA, convenient and promising methods for preparing variousN-, O-, P-, S-, andC-alkylated and arylated substances have been developed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1411–1422, August, 1995.The author is grateful to Professor V. A. Dorokhov, Professor V. P. Litvinov, and researchers from the laboratories of N. D. Zelinsky Institute of Organic Chemistry headed by them, who participated in joint studies.The work was carried out with financial support from the International Science Foundation (Grant No. MHYOO). 相似文献
2.
N. A. Gasviani M. Sh. Khutsishvili L. M. Abazadze 《Russian Journal of Electrochemistry》2006,42(9):931-937
Electrochemical reduction of sodium metavanadate in an equimolar KCl-NaCl melt and the effect of acid-base properties of environment on this process are studied by a voltammetry method on a stationary platinum electrode. It is established that the limiting current of the NaVO3 electroreduction process has a kinetic nature. The process proceeds via an autoinhibition scheme and its rate is limited by an acid-base reaction conjugated with an irreversible charge transfer reaction. A substantial role of cationic composition of the melt is revealed experimentally. Following acidification of the KCl-NaCl-NaVO3 melt by Mg2+ (from MgCl2), the process passes from an irreversible kinetic regime into a reversible diffusion (quasi-diffusion) process. Values of stability constants for vanadates produced with the aid of acid-base titration of vanadium pentoxide by oxygen ions in experimental conditions are presented. These values are taken into account when calculating kinetic parameters of the NaVO3 electroreduction. 相似文献
3.
Yu. M. Kargin E. I. Gritsenko V. V. Yanilkin V. V. Plemenkov L. K. Dubovik N. I. Maksimyuk B. M. Garifullin Sh. K. Letypov A. V. Il'yasov 《Russian Chemical Bulletin》1992,41(9):1572-1579
The electrochemical reduction of 1,1-dihalo-2-R-2-methylcyclopropanes was studied by polarography and preparative electrolysis. A mixture of stereoisomeric monoboro- and monochlorocyclopropanes was obtained with preparative yield of 60–70% in preparative electroreduction in methanol against a background of 0.1 M LiClO4. In the case of bromine derivatives of cyclopropanes (except when R = CN) an effect was found on the part of the current density on the ratio of cis and trans isomers, which was interpreted as a change, in dependence on current density, of the contributions of the reactions of reduction of the starting compounds (SN2 mechanism) and ionic pairs (SN1 mechanism). The effect of the solvent (CHCl3, DMF, DMSO, MeOH) and background salt (LiClO4, Et4NBr) on the ratio of stereoisomers is in agreement with this interpretation.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2023–2032, September, 1992. 相似文献
4.
M. N. Elinson S. K. Fedukovich Z. A. Starikova A. N. Vereshchagin P. A. Belyakov S. V. Gorbunov G. I. Nikishin 《Russian Chemical Bulletin》2006,55(1):106-111
Electrolysis of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acid esters in alcohols in an undivided cell in the
presence of NaBr or NaOAc afforded 6-substituted (1R,5R, 6R)*-4,4-dialkoxy-5-cyano-2-oxo-3-azabicyclo[3.1.0]hexane-1-carboxylic acid esters in 80–95% yields.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–107, January, 2006. 相似文献
5.
6.
V. G. Nefedov O. A. Artyushenko E. V. Kashevarova 《Russian Journal of Electrochemistry》2006,42(6):638-642
Mass transfer to a horizontal electrode during electrolytic evolution of oxygen and hydrogen at current densities of 100 to 10 000 A/m2 is studied. The mass transfer intensity is evaluated from the diffusion layer thickness, which varies from 60 to 5 μm at such current densities. Calculations show that the decrease in the diffusion layer thickness is due to bubbles with a stationary interphase surface crossing the diffusion layer. During the hydrogen evolution, the diffusion layer thickness is nearly the same for vertical and horizontal electrodes. During the oxygen evolution, the diffusion layer is much thinner for a horizontal electrode. Additional decrease of the diffusion layer thickness during the evolution of oxygen is associated with the lesser solution density in the near-electrode layer and with its transport away by means of natural convection. 相似文献
7.
Metal (M) oxide (M: Ir, Os, Pd, Pt, Rh, Ru) together with MaO2 and MnO2 alone, were coated on SnO2 films and the anode behavior was examined in 1.0 N H2SO4, 1.0 N NaOH and 1.0, N NaCl aqueous solutions at 25°. The results are compared with those of DSA and of metallic Pt. 相似文献
8.
A. I. Ilovaisky V. M. Merkulova Yu. N. Ogibin G. I. Nikishin 《Russian Chemical Bulletin》2005,54(7):1585-1592
Electrolysis of salts of primary and secondary nitro compounds (nitroethane, 1- and 2-nitropropanes, nitrocyclohexane, and
nitrocycloheptane) in the presence of excess halide, nitrite, cyanide, and phenylsulfinate anions under undivided and divided
amperostatic electrolysis conditions in a two-phase medium (CH2Cl2/H2O) produces geminal nitrohalides (35–85% yields), dinitro compounds (15–51%), nitronitriles (6–27%), and nitrosulfones (50–70%).
The salts of secondary nitro compounds form the products of oxidative coupling with halide and phenylsulfinate anions under
the undivided electrolysis conditions. In all other cases, divided electrolysis is required.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1539–1546, July, 2005. 相似文献
9.
Benzathine is prepared in good yields from cyanobenzene by a combination of electrochemical hydrogenation and Kolbe electrolysis using nickel and platinum electrodes in the presence of methanolic sodium methoxide in an undivided cell. 相似文献
10.
Marián Kucharík František Šimko Vladimír Danielik Miroslav Boča Roman Vasiljev 《Monatshefte für Chemie / Chemical Monthly》2007,138(12):1211-1215
Summary. The phase diagram of the system Na3AlF6–NaVO3 was determined by means of thermal analysis. The system is a simple binary eutectic one. The eutectic point was estimated
at x(NaVO3) = 0.975 and t
eut = 617°C. The XRD patterns of samples after thermal analysis revealed the presence of cryolite and NaVO3 only supporting the above assumption of a simple eutectic binary system. 相似文献