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Photoinduced NH tautomerism, along with the reaction pathways of phototautomerization in tetrabenzoporphin and porphin free bases in n-octane polycrystalline matrices at 77 K, is studied by simulation of kinetic processes and their experimental observation. The simulation of the processes is performed by the numerical solution of the system of kinetic equations describing the populations of electronic levels and transitions between them. Kinetic dependences are obtained by measuring the perturbation of stationary fluorescence of one component of the 0-0 doublet origin upon pulsed selective photoexcitation of the other component. For two tautomeric forms related by the reversibility of the photochemical reaction, under the assumption of synchronism of the NH rearrangement, (i) analytical solutions governing the reaction rate are found, (ii) a method of measuring the rate constants of the proton rearrangement is suggested and the constants themselves are estimated, and (iii) direct evidence of the participation of T 1 levels in the photochemical reaction is obtained. With the aid of numerical simulations, the specific features of kinetic manifestation of an asynchronous mechanism of the photoinduced NH rearrangement are studied. 相似文献
3.
Kleitz F Solovyov LA Anilkumar GM Choi SH Ryoo R 《Chemical communications (Cambridge, England)》2004,(13):1536-1537
Exceptional control of the phase behavior of highly ordered large pore mesostructured silica (with the choice of Fm3m, Im3m or p6mm symmetry) is achieved using a triblock copolymer (EO(106)PO(70)EO(106)) and butanol at low acid concentrations. 相似文献
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Calculations of the hypersurface of the adiabatic potential which determines the movement of NH protons in the centre of the porphin molecule are carried out by the CNDO/2 method. Simultaneous displacements of two NH protons and the displacement of only one proton are considered. The barrier heights for NH tautomerism in these two cases are evaluated, as well as the frequencies of NH vibrational modes for a porphin molecule of D2h symmetry. The data obtained indicate that shifts of the central protons from one nitrogen atom to another occur almost independently of each other, and the degenerate rearrangement A → B proceeds in a stepwise way, via the intermediate isomer C with adjacent disposition of NH protons (see Fig. 1). The role of tunnelling through the barrier in this process is emphasized. The electronic absorption spectra of the two porphin isomers of D2h and C2v symmetry are calculated using the CNDO/S method. 相似文献
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Solovyov A. V. Markov A. B. Yakovlev E. V. Maksimov O. Y. 《Russian Physics Journal》2020,63(2):270-275
Russian Physics Journal - Results of investigations of acoustic signals induced in a copper plate irradiated with a microsecond lowenergy high-current electron beam (LEHCEB) are presented. The... 相似文献
7.
O.I. Kalchenko S.O. Cherenok A.V. Solovyov V.I. Kalchenko 《Supramolecular chemistry》2013,25(5-6):409-413
Host–guest complexation process of 5,17-bis-(N-tolyliminomethyl)-25,27-dipropoxycalix[4]arene with pyridine carboxylic acids by RP HPLC method (mobile phase – MeCN/H2O, 86/14 by volume, LiChrosorb RP 18, UV detector, λ = 254 nm) had been studied. The binding constants and Gibbs free energies of the complexes 5,17-bis(N-tolyliminomethyl)-25,27-dipropoxycalix[4]arene with the pyridine carboxylic acids are within 584 to 1914 M? 1 and ? 15.76 to ? 18.69 kJ/mol, respectively. It was shown by the molecular modelling that the complexes are stabilised by hydrogen bonds between carboxylic groups of the acids and nitrogen atoms of imino groups at the upper rim or oxygen atoms of the hydroxyl groups at the lower rim of the macrocycle. Linear dependence of the binding constants from the acid lipophilicity log P indicates the role of solvophobic interactions during the complexation process. 相似文献
8.
Bekzat ABDIKADYR Alp KILI Onur ALEV Serkan BÜYÜKK
SE Zafer Ziya
ZTÜRK 《Turkish Journal of Chemistry》2021,45(2):295
Pristine and WO3 decorated TiO2 nanorods (NRs) were synthesised to investigate n-n-type heterojunction gas sensing properties. TiO2 NRs were fabricated via hydrothermal method on fluorine-doped tin oxide coated glass (FTO) substrates. Then, tungsten was sputtered on the TiO2 NRs and thermally oxidised to obtain WO3 nanoparticles. The heterostructure was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. Fabricated sensor devices were exposed to VOCs such as toluene, xylene, acetone and ethanol, and humidity at different operation temperatures. Experimental results demonstrated that the heterostructure has better sensor response toward ethanol at 200 °C. Enhanced sensing properties are attributed to the heterojunction formation by decorating TiO2 NRs with WO3. 相似文献
9.
Shabatina T. I. Morozov Yu. N. Solovyov A. V. Shabatin A. V. Vernaya O. I. Fedorov V. V. Melnikov M. Ya. 《Moscow University Chemistry Bulletin》2021,76(3):196-202
Moscow University Chemistry Bulletin - A combined cryochemical method is proposed for the dimensional and structural modification of drugs. This method forms a molecular flow of a substance... 相似文献
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