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71.
Kasumov VT Köksal F 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(1-2):31-39
New bidentate N-(2,6-di-phenyl-1-hydroxyphenyl) salicylaldimines bearing X=H and 3,5-di-t-butyl substituents on the salicylaldehyde ring, L(x)H, and their copper(II) complexes, M(Lx)2, (M=Cu(II), Co(II), Pd(II), Ni(II) and Zn(II)) have been synthesized and characterized by IR, UV/vis, 1H NMR, 13C NMR, ESR spectroscopy, magnetic susceptibility measurements, as well as their oxidation with PbO(2) and reduction (for Cu(Lx)2) with PPh(3) were investigated. ESR studies indicate that oxidation of M(Lx)2 produces ligand-centered M(II)-phenoxyl radical species. The Cu(Lx)2 complexes, unlike others M(Lx)2, are readily reduced by PPh3 via intramolecular electron transfer from ligand to copper(II) to give unstable radical intermediates which are converted to another stable secondary radical species. The analysis of ESR spectra of Cu(Lx)(2), Co(L1)(2) and generated phenoxyl radicals are presented. 相似文献
72.
The synthesis and characterization (elemental analysis, i.r., u.v., magnetic measurements and cyclic voltammetry) of some new CoII complexes with bidentate bulky salicylaldimines derived from 3,5-di-t-butylsalicylaldehyde and o- or p-substituted (X = Cl, Me, OMe, But) aniline derivatives are reported in this paper. The presented ligands show very low complexation ability in respect of NiII, VOII, MnII, ZnII and CdII metal ions. Electrochemical studies on the complexes, though revealing a dependence of the metal centered redox potentials on electronic and steric effects of the aniline substituents X, the potentials of the ligand-centered oxidation do not correlate with the electronic effects of X. 相似文献
73.
A. N. Chekhlov T. M. Kasumov V. K. Brel N. S. Zefirov 《Journal of Structural Chemistry》1996,37(5):800-806
Crystal and molecular structure of μ-oxo-bis[trifluoroacetato(p-tolyl)iodine] (I) synthesized by a new procedure was determined by X-ray diffraction analysis. Crystals I are orthorhombic, unstable, space group Pbcn, a=17.684(3), b=8.453(3), c=30.560(4) Å, Z=8. The structure of I was solved by direct and Fourier methods and refined by the full-matrix least-squares procedure in an anisotropic-isotropic approximation to R=0.098 (CAD-4 automatic diffractometer, λCuKα, 1200 observed reflections with I≥2σ). In molecule I, two iodine atoms have T-configuration of valence bonds with the average bond angles O?I?O 169(1) and O?I?C 86(2)°, average bond lengths I?Oμ 2.009(9), I?Oacet 2.269(9), and I?Caryl 2.11(1) Å, and the bond angle I?O?I 118.1(5)°. In molecule I, two p-Tol substituents are directed to approximately the same side of the medium plane of the central O?I?O?I?O fragment. Crystal structure I has I...O type intra-and intermolecular nonvalent interactions (secondary bonds). 相似文献
74.
CaC2O4真空热分解中,第一阶段生成的CO中47%歧化成CO2和C;第二阶段生成的CO与第一阶段生成的C发生气化反应,发生反应的比例随样品量增加而增大。用CaCO3标定CO后再用CaC2O4标定CO可以排除这些干扰。本文提出了一个对任意气体标定的方法。 相似文献
75.
Several new binuclear CuII, NiII, OVIV and MnII complexes of tridentate salicylaldimine (H2L), obtained from 3,5-di-t-butylsalicylaldehyde and o-aminophenol, have been prepared and characterized by analytical, spectroscopic (i.r., u.v.–vis., e.s.r.) techniques, magnetic and thermal measurements. The adduct formation or dissociation of these complexes in the presence of strongly coordinating solvents like pyridine and DMSO did not take place. The complexation of CoII with H2L is accompanied by intramolecular electron transfer from the metal to the coordinated ligand yielding the radical ligand CoIII complex (g = 2.003, A
Co = 10 G). The e.s.r. spectra of the CuII, OVIV and MnII complexes in the solid state and in solution are very broad due to intramolecular dipolar antiferromagnetic interactions. 相似文献
76.
A. A. Davydov A. A. Efremov F. B. Kasumov K. Yu. Adzhamov 《Reaction Kinetics and Catalysis Letters》1982,18(1-2):29-32
Infrared spectroscopic studies of the nature of catalyst centers indicate the presence of Brönsted and Lewis acid centers on the surface. Propylene conversion to acetone proceeds via proton transfer from the surface to propylene with the formation of a (CH3)2–C(H)–O–Me type compound, and its subsequent dehydration.
- , . (CH3)2–C(H)–OMe .相似文献
77.
A. V. Volynskaya E. A. Kasumov A. V. Shishkov 《Russian Journal of General Chemistry》2007,77(11):2017-2026
Unfolding of polypeptide chain of ribonuclease A in urea and guanidinium chloride (GuCl) solutions under equilibrium conditions involves formation of intermediates whose properties (compactness and preservation of the most of the native hydrophobic core, secondary structures, and native-like folding of the polypeptide chain) correspond to the basic characteristics of the “molten globule” state. Intermediates are “damp” molten globules (with water molecules inside the globule). The examinations performed revealed pronounced distinctions in the properties of the intermediates, above all, in their compactness degrees. 相似文献
78.
79.
80.
Ismail G. Mursakulov M.M. Guseinov N.K. Kasumov Nikolai S. Zefirov V.V. Samoshin E.G. Chalenko 《Tetrahedron》1982,38(14):2213-2220
The position of the conformational equilibria in a series of 2-substituted cyclohexanone ketals have been determined by 1H NMR. For the ethylene ketals 6 the equatorial conformer has been found to be enthalpically preferred. The other ketal system (5, 7–9), in contrast, display predominance of axial conformers. The reasons for this behavior are discussed in terms of rotameric conformations of acetal chains. 相似文献