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101.
Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2020,58(6):478-499
This is the first part of two closely related reviews dealing with the computation of phosphorus-31 nuclear magnetic resonance chemical shifts in a wide series of organophosphorus compounds including complexes, clusters, and bioorganic phosphorus compounds. In particular, the analysis of the accuracy factors, such as substitution effects, solvent effects, vibrational corrections, and relativistic effects, is presented. This review is dedicated to the Full Member of the Russian Academy of Sciences Professor Boris A. Trofimov in view of his invaluable contribution to the field of synthesis, nuclear magnetic resonance, and computation studies of organophosphorus compounds. 相似文献
102.
Rusakov YY Krivdin LB Schmidt EY Mikhaleva AI Trofimov BA 《Magnetic resonance in chemistry : MRC》2006,44(7):692-697
Conformational study of 2-(2-pyrrolyl)pyridine and 2,6-di(2-pyrrolyl)pyridine was performed on the basis of the experimental measurements and high-level ab initio calculations of the one-bond 13C-13C, 13C-1H and 15N-1H spin-spin coupling constants showing marked stereochemical behavior upon the internal rotation around the pyrrole-pyridine interheterocyclic bonds. Both compounds were established to adopt predominant s-cis conformations with no noticeable out-of-plane deviations. 相似文献
103.
Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2019,57(11):897-914
This is the first one of the three closely interrelated reviews to be published in Magnetic Resonance in Chemistry dealing with accordingly theoretical background, chemical applications, and biochemical studies of and by means of computational 1H NMR. Presented in the first part of the review is a general outline of the modern theoretical methods and accuracy factors of computational 1H NMR involving locally dense basis set schemes, solvent effects, vibrational corrections, and relativistic effects performed at the density functional theory and/or nonempirical levels. This review is dedicated to Prof. Stephan Sauer in view of his invaluable contribution to the field of computational nuclear magnetic resonance. 相似文献
104.
Stepan A. Ukhanev Sergei V. Fedorov Yuriy Y. Rusakov Irina L. Rusakova Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2022,60(9):901-914
All possible spin–spin coupling constants, 19F–19F, 19F–13C, and 19F–1H, of pentafluorobenzene were calculated at five different levels of theory, HF, DFT, SOPPA (CCSD), CCSD, and the SOPPA (CCSD)-based composite scheme with taking into account solvent, vibrational, relativistic, and correlation corrections. Most corrections were next to negligible for the long-range couplings but quite essential for the one-bond carbon–fluorine coupling constants. Hartree–Fock calculations were found to be entirely unreliable, while DFT results were comparable in accuracy with the data obtained using the wave function-based methods. 相似文献
105.
Indirect relativistic bridge and substituent effects from the ‘heavy’ environment on the one‐bond and two‐bond 13C1H spin–spin coupling constants 下载免费PDF全文
Irina L. Rusakova Yury Yu. Rusakov Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2016,54(1):39-45
Indirect relativistic bridge effect (IRBE) and indirect relativistic substituent effect (IRSE) induced by the ‘heavy’ environment of the IV‐th, V‐th and VI‐th main group elements on the one‐bond and geminal 13C? 1H spin–spin coupling constants are observed, and spin‐orbit parts of these two effects were interpreted in terms of the third‐order Rayleigh–Schrödinger perturbation theory. Both effects, IRBE and IRSE, rapidly increase with the total atomic charge of the substituents at the coupled carbon. The accumulation of IRSE for geminal coupling constants is not linear with respect to the number of substituents in contrast to the one‐bond couplings where IRSE is an essentially additive quantity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
106.
Yury Yu. Rusakov Leonid B. Krivdin Ambati Ashok Kumar László Szilágyi Katalin E. Kövér 《Magnetic resonance in chemistry : MRC》2012,50(7):488-495
Unambiguous resonance assignments of diastereotopic CH2 protons in the anomeric side chain of nine alkyl‐ and aralkylselenoglycosides have been carried out on the basis of experimental CPMG‐HSQMBC measurements and theoretical second order polarization propagator approach (SOPPA) calculations of geminal 77Se‐1H spin‐spin coupling constants involving diastereotopic pro‐R and pro‐S protons. Theoretical conformational analyses have been performed at the MP2/6‐311G** level. The conformational space of each of the selenoglycosides under study could be adequately described as a mixture of six interconverting conformers with the molar fractions depending on the nature of the side chain substituent at the selenium atom. The good agreement observed between measured and the weighted conformational averaged values of the calculated coupling constants provides a basis for reliable diastereotopic assignments in this type of carbohydrate structures. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
107.
K. A. Chernyshev B. A. Gostevskii L. B. Krivdin 《Russian Journal of Organic Chemistry》2013,49(6):832-837
Dynamic equilibria related to change of the coordination number of the silicon atom in bis[N-(dimethylamino) imidato-N′,O]silacycloalkanes in solution were studied by theoretical calculations and experimental measurement of the 29Si NMR chemical shifts. Silacyclopentane derivatives were found to exist in solution as mixtures of species with six- and five-coordinate silicon atoms, and silacyclohexane derivatives, as mixtures of five- and four-coordinate silicon compounds. 相似文献
108.
Boris A. Trofimov Lyubov' N. Sobenina Al'bina I. Mikhaleva Ol'Ga V. Petrova Vladislav N. Drichkov Igor A. Ushakov Ol'Ga A. Tarasova Darya‐Suren D. Toryashinova Yuriy Yu. Rusakov Leonid B. Krivdin 《Journal of heterocyclic chemistry》2007,44(3):505-513
2‐(2‐Cyano‐1‐ethylthioethenyl)pyrroles are readily coupled (50–55°) with primary and secondary amines at the position 1 of the ethenyl moiety to eliminate ethanethiol and afford 2‐(1‐amino‐2‐cyanoethenyl)pyrroles and/or their cyclic isomers ‐ functionalized 1‐amino‐3‐iminopyrrolizines in good to high yields. 相似文献
109.
V. A. Semenov D. O. Samul’tsev L. B. Krivdin 《Russian Journal of Organic Chemistry》2014,50(3):381-388
Effects of solvation on the accuracy of the calculation of 15N chemical shifts in the azine series have been analyzed at the DFT/GIAO level of theory. The best results are obtained with the use of the Keal-Tozer KT2 functional in combination with the Dunning aug-cc-pVTZ basis set with inclusion of solvent effects according to the Tomasi polarizable continuum model (PCM). If specific solvation is strong, additional consideration of solvent effects in the supermolecule approximation is necessary with explicit inclusion of solvent molecules. 相似文献
110.