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E. E. Starodubets S. V. Borisevich M. S. Shapnik 《Russian Journal of Inorganic Chemistry》2009,54(3):453-458
Quantum-chemical calculations of various forms and isomers of ethylenediamine (En) and structures of ethylenediamine zinc(II) complexes existing over a wide pH range (0–14) have been performed using the density functional theory in the PBE version. The structural, energetic, and charge characteristics of the stable forms of complexes are presented. 相似文献
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Yanina V. Burgart Galina F. Makhaeva Olga P. Krasnykh Sophia S. Borisevich Natalia A. Agafonova Nadezhda V. Kovaleva Natalia P. Boltneva Elena V. Rudakova Evgeny V. Shchegolkov Galina A. Triandafilova Denis A. Gazizov Olga G. Serebryakova Maria V. Ulitko Sergey L. Khursan Victor I. Saloutin Rudy J. Richardson 《Molecules (Basel, Switzerland)》2022,27(22)
One of the powerful antioxidants used clinically is Edaravone (EDA). We synthesized a series of new EDA analogs, 4-aminopyrazol-5-ol hydrochlorides, including polyfluoroalkyl derivatives, via the reduction of 4-hydroxyiminopyrazol-5-ones. The primary antioxidant activity of the compounds in comparison with EDA was investigated in vitro using ABTS, FRAP, and ORAC tests. In all tests, 4-Amino-3-pyrazol-5-ols were effective. The lead compound, 4-amino-3-methyl-1-phenylpyrazol-5-ol hydrochloride (APH), showed the following activities: ABTS, 0.93 TEAC; FRAP, 0.98 TE; and ORAC, 4.39 TE. APH and its NH-analog were not cytotoxic against cultured normal human fibroblasts even at 100 μM, in contrast to EDA. According to QM calculations, 4-aminopyrazolols were characterized by lower gaps, IP, and η compared to 4-hydroxyiminopyrazol-5-ones, consistent with their higher antioxidant activities in ABTS and FRAP tests, realized by the SET mechanism. The radical-scavenging action evaluated in the ORAC test occurred by the HAT mechanism through OH bond breaking in all compounds, directly dependent on the dissociation energy of the OH bond. All the studied compounds demonstrated the absence of anticholinesterase activity and moderate inhibition of CES by some 4-aminopyrazolols. Thus, the lead compound APH was found to be a good antioxidant with the potential to be developed as a novel therapeutic drug candidate in the treatment of diseases associated with oxidative stress. 相似文献
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A. L. Chuiko L. P. Filonenko A. N. Borisevich M. O. Lozinskii 《Russian Journal of General Chemistry》2009,79(1):72-77
Isomerism of thioureas bearing a methylenebisphosphonic group was studied. It was shown that a change in the ionization degree of the bisphosphonic group affects the strength of intramolecular hydrogen bonds and Z/E ratio in the solution. 相似文献
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Rimma Sultanova Sophia Borisevich Gulnara Raskil'dina Julianna Borisova Irina Baykova Leonid Spirikhin Sergey Khursan Simon Zlotsky 《中国化学会会志》2020,67(7):1144-1151
Experimental and theoretical aspects of the condensation of glycerol and its homologs (1,2,3- and 1,2,4-butanetriols) with formaldehyde and acetone are studied under conditions of acid catalysis. Calculation of the thermodynamic parameters of the resulting products by the composite method CBS-QB3 shows that the six-membered heterocycles, the products of the interaction of triols with formaldehyde, are thermodynamically more stable than the five-membered acetals, while the reaction of the same triols with acetone is preferable for the formation of the five-membered acetals. This is due to the fact that the regioselectivity of the studied reactions is determined by the structural features and reactivity of the carbocations formed in a condensed medium during the course of the reaction. According to the theoretical data obtained experimentally, during the condensation of glycerol and 1,2,4-butanetriol with formaldehyde in the most stable form of the six-membered cyclic carbocation, intramolecular hydrogen bonding and anomeric stabilization due to the axially oriented hydroxyl group take place. As a result, cation 1b–1 is 1.2–1.6 kJ/mol more stable than its five-membered isomers ( 1a–1 and 1b–2 ). It leads to the predominant formation of 1,3-dioxane ( 3b ). However, upon condensation of butanetriol-1,2,3 with formaldehyde, the intermediate cation 4a–1 turns out to be significantly more stable than the other isomers due to the strong intramolecular hydrogen bond in the six-membered ring with the participation of the hydroxyl group of the substituent and the hydroxyl group of the cationic center, leading to the predominant formation of the dioxolane 6a . 相似文献
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N. A. Borisevich G. G. Dyachenko V. A. Petukhov M. A. Semenov 《Optics and Spectroscopy》2008,105(6):859-866
The fluorescence and fluorescence excitation spectra of jet-cooled chrysene are measured. The frequencies of in-plane vibrations in the ground and first excited singlet electronic states, as well as the relative intensities of transitions between them, are calculated with the MO/M8ST method. Based on these data, experimental spectra are interpreted. In the fluorescence excitation spectrum, the position of the line of the 0–0 transition (28 195 ± 1 cm?1), which is the most intense, is determined. In the experimental fluorescence excitation spectrum, 21 lines correspond to fundamental vibrations (altogether, 37 lines are attributed). This supports our assignment and is consistent with the group-theoretical analysis of vibronic interactions. Upon excitation at the frequency of the 0–0 transition, 10 lines corresponding to the excitation of fundamental vibrations are detected, and all 17 lines observed are attributed. In the fluorescence excitation spectrum, the standard deviation between the calculated and measured frequencies of attributed fundamental vibrations is 19 cm?1, while that in the fluorescence spectrum is 15 cm?1. 相似文献