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41.
V. M. Petrov N. I. Giricheva G. V. Girichev V. N. Petrova S. N. Ivanov A. V. Bardina 《Journal of Structural Chemistry》2011,52(1):60-68
A combined gas electron diffraction and quantum chemical (B3LYP/6-311+G**, B3LYP/cc-pVTZ) study of the molecular structure of 2-nitrobenzenesulfonic acid (2-NBSA) is performed. Quantum chemical calculations show that the 2-NBSA molecule has five conformers, and the Gibbs energy of one of them is lower by more than 4.5 kcal/mol than the energy of the other conformers. It is found experimentally that the saturated vapor of 2-NBSA at T = 394(5) K contains only the low-energy conformer that has an intramolecular hydrogen bond between the H atom of the hydroxyl group and one of the O atoms of the NO2 group. The C-C-S-O(H) torsion angle determining the position of the S-O(H) bond is ?72(7)°, while the NO2 group is substantially turned relative to the benzene ring plane (C1-C2-N-O = 40(5)°). The following experimental values of the internuclear distances are obtained for this conformer (Å): r h1(C-H)av = 1.07(2), r h1(C-C)av = 1.401(4), r h1(C-S) = 1.767(6), r h1(S=O)av = 1.412(4), r h1(S-O) = 1.560(6), r h1(N-O)av = 1.217(5), r h1(C-N) = 1.461(8), r h1(O-H) = 0.99(3). 相似文献
42.
N. I. Giricheva G. V. Girichev N. P. Kuzmina Yu. S. Medvedeva A. Yu. Rogachev 《Journal of Structural Chemistry》2009,50(1):52-59
In the framework of synchronous gas-phase electron diffraction and mass spectrometry experiment, the saturated vapor of N,N′-ethylenebis(salicylaldiminate) copper(II) CuO2N2C16H14 is studied at a temperature T 574(5) K. It is found that evaporation is congruent and the saturated vapor consists of monomeric molecules. Electron diffraction data are proved to correspond to the geometric model for the CuO2N2C16H14 molecule of C 2 symmetry with an almost planar structure of the CuN2O2 coordination fragment and internuclear distances \(r_{h_1 } \)(Cu-O) = 1.917(13) Å and \(r_{h_1 } \)(Cu-N) = 1.931(15) Å. The stuctural parameters obtained are compared to those quantum chemically calculated and molecular parameters in crystals. 相似文献
43.
M. S. Fedorov N. I. Giricheva E. A. Lapykina M. S. Korableva 《Optics and Spectroscopy》2018,125(1):34-41
Particular features of the geometrical and electronic structure of six possible conformers of dansylamide ((CH3)2N–C10H6–SO2NH2) are considered. The electronic absorption spectra of the conformers of dansylamide in the free state and taking into account the influence of an aqueous solvent (in terms of the PCM model) are calculated by the TDDFT method. It is shown that, as a result of taking into account solvation, the electronic absorption spectra of the conformers exhibit a bathochromic shift, and the difference in the values of λ of the conformers reaches 16 nm. The calculated electronic absorption spectra in an aqueous medium agree qualitatively with the obtained experimental spectra. An analysis of molecular orbitals involved in the first three electronic transitions of the conformers is carried out. It is suggested that the broadening of the band with λmax = 326 nm in the experimental spectrum may be caused by the presence of dansylamide conformers in the aqueous solution. It is shown that the calculated values of λ in the electronic absorption spectra of dansylamide in the aqueous solvent depend substantially on the DFT functional type. 相似文献
44.
M. S. Fedorov N. I. Giricheva E. A. Lapykina O. A. Suvorova 《Optics and Spectroscopy》2017,123(2):231-237
Geometrical and electronic structure and optical properties of several substituents and derivatives of 1,8-naphthosultam are studied by quantum-chemical DFT and TDDFT. It is found that the substituents –NO2, –CF3, and –N(CH3)2 affect the geometrical and electronic structure the most. It is shown that the Stokes shift is greatest (≈260 nm) for compounds with the strong donor substituent –N(CH3)2, while strong acceptor substituents provide a quite small Stokes shift. The dependence of the Stokes shift on the difference in energies of the frontier orbitals of the ground and excited states of molecules is found. Of the 1,8-naphthosultam substituents considered, compounds with –N(CH3)2 substituent, which emit in the biological window region, can be advised for use in optical bioimaging. The results can be used as a basis for the development and creation of new functional materials and biologically active compounds. 相似文献
45.
V. M. Petrov N. I. Giricheva V. N. Petrova G. V. Girichev 《Journal of Structural Chemistry》1992,32(4):494-498
Ivanovo Chemical Technology Institute. Ivanovo State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 4, pp. 51–55, July–August, 1991. 相似文献
46.
Simultaneous electron diffraction and mass-spectrometric study of the structure of the MoF5 molecule
Electron diffraction data for the MoF5 molecule are analyzed in terms of an ra structure. Three models of the geometrical structure, which have D3h, C4v, and C2v symmetry, are considered. It is confirmed that a distorted bipyramid of C2v symmetry is the best model that is in agreement with experimental electron diffraction data. The model has three different types of nuclear Mo-F distances: rα(Mo-F1eq) = 1.720(5) Å, rα(Mo-F2eq) = 1.826(7) Å, rα(Mo-Fax) = 1.825(7) Å. The bond angle between the pseudoaxial bonds is 168.1(0.6)?, and the angle between the Mo-F2eq pseudoequatorial bonds is 122.6(0.8)?. The ra(Mo-Fleq) and ra(Mo-F2eq) distances differ significantly. Possible reasons for this are discussed. 相似文献
47.
48.
49.
V. M. Petrov N. I. Giricheva E. G. Rakov G. V. Girichev E. I. Melnichenko 《Journal of Structural Chemistry》1993,34(3):372-377
The saturated vapor over solid W
2
O
4
F has been studied by electron diffractometry. Structure analysis was fulfilled assuming complex composition of the vapor. It has been established that at T=1043±30 K the vapor consists of WO
2
F
2
and WOF
4
molecules in amounts of 90 and 10 more % respectively. There are two alternative models describing the geometrical structure of the WO
2
F
2
molecule (C
2v symmetry) which fit experimental data equally well. In one model, the valence OWO angle is greater than the FWF angle, while in the other, the inverse relation is observed.Ivanovo State University. Moscow Mendeleev Chemical Engineering Institute. Ivanovo Chemical Engineering Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 41–46, May–June 1993.Translated by L. Smolina 相似文献
50.
Zakharov Alexander V. Vogt Natalja Shlykov Sergey A. Giricheva Nina I. Vogt Jürgen Girichev Georgiy V. 《Structural chemistry》2003,14(2):193-197
The structural investigation of molecules in the vapor over neodymium tribromide was performed by synchronous gas-phase electron diffraction and mass spectrometric (GED/MS) experiments at 1110(10) K. Besides the monomeric molecules (NdBr3), a small amount (0.7%) of the dimer (Nd2Br6) was detected. For NdBr3, the thermal-average bond length r
g
(Nd–Br) of 2.675(6) Å was determined. The equilibrium structure was estimated to be planar (or nearly planar) with r
e
(Nd–Br) of 2.659(7) Å. Three vibrational frequencies were estimated using the GED data: 1 = 193 cm–1, 2 = 35 cm–1, 4 = 41 cm–1. The structural parameters of Nd2Br6 could not be refined and were constrained at the estimated values during the analysis. 相似文献