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101.
R. K. Strizhakov E. V. Tretyakov A. S. Medvedeva V. V. Novokshonov V. G. Vasiliev V. I. Ovcharenko O. A. Krumkacheva M. V. Fedin E. G. Bagryanskaya 《Applied magnetic resonance》2014,45(10):1087-1098
A method for synthesis of new covalently linked spin-labeled cyclodextrin (CD) via the attachment of nitronyl nitroxide 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl to permethylated β-cyclodextrin is described. Electron spin echo envelope modulation (ESEEM) studies demonstrate that the new spin-labeled CD exhibits dynamic equilibrium between conformations with radical fragment capping the cavity of CD and radical fragment located outside the cavity. In solution, nitronyl nitroxide attached to CD retains its sensitivity to nitric oxide (NO), as reaction with NO leads to formation of iminonitroxide fragment evidenced by continuous-wave (CW) electron paramagnetic resonance (EPR). At the same time, CW EPR study of the reaction with ascorbic acid shows that the described binding of nitronyl nitroxide to CD does not provide higher stability of radical towards the reduction, and the corresponding rate constants are close to those obtained for free nitronyl nitroxide. Plausible explanations of these observations are discussed. 相似文献
102.
Zvereva EA Evstigneeva MA Nalbandyan VB Savelieva OA Ibragimov SA Volkova OS Medvedeva LI Vasiliev AN Klingeler R Buechner B 《Dalton transactions (Cambridge, England : 2003)》2012,41(2):572-580
Two synthetic routes-ion-exchange preparation from layered Na(3)Ni(2)SbO(6) at 300 °C and direct solid-state synthesis at 1150 °C resulted in layered Li(3)Ni(2)SbO(6), a cation-ordered derivative from the rocksalt type. The Fddd form reported earlier could not be reproduced. According to the XRD Rietveld analysis, Li(3)Ni(2)SbO(6) is a pseudohexagonal monoclinic structure, C2/m, with a = 5.1828(2) ?, b = 8.9677(3) ?, c = 5.1577(2) ?, β = 109.696(2)°. No Li/Ni mixed occupancy was detected. At high temperatures, the magnetic susceptibility follows the Curie-Weiss law with a positive value of Weiss temperature, ~8 K, indicating a predominance of ferromagnetic interactions. However, Li(3)Ni(2)SbO(6) orders antiferromagnetically at T(N)~ 15 K. The effective magnetic moment is 4.3 μ(B)/f.u. which satisfactorily agrees with theoretical estimations assuming high-spin configuration of Ni(2+) (S = 1). Electron spin resonance (ESR) spectra show single Lorentzian shape line attributed to Ni(2+) ion in octahedral coordination. The absorption is characterized by isotropic temperature independent effective g-factor g = 2.150 ± 0.005. In accordance with the layered honeycomb crystal structure determined for Li(3)Ni(2)SbO(6), the superexchange interaction between Ni(2+) ions through Ni-O-Ni pathways within Ni(2)SbO(6) layers are assumed to be ferromagnetic, while the dominant interaction between layers is antiferromagnetic. 相似文献
103.
S. I. Kuznetsov R. Kh. Yumagulova F. F. Khamidullin Yu. A. Lebedev N. A. Medvedeva S. V. Kolesov 《Polymer Science Series A》2012,54(10):798-802
Poly(methyl methacrylate) and polystyrene functionalized by fullerene C60 tend to form micellar structures comprising a fullerene cluster as a core and a macromolecular shell. Films prepared from PMMA-C60 and PS-C60 micellar solutions are polymer matrices with fullerene-containing globular structures uniformly distributed in the polymer bulk. 相似文献
104.
Ivanovskii A. L. Medvedeva N. I. Sofronov A. A. 《Russian Journal of Coordination Chemistry》2001,27(2):112-115
A quantum–chemical zone and cluster approaches were used to model the electronic energy spectrum and to study the chemical bond in a hypothetical phase of titanium dicarbide (TiC2) composed of C2dimers as structural units. The effect of orientational disorder of the C2dimers on the electronic structure and chemical stability of the dicarbide was investigated. 相似文献
105.
Yaroslav V. Kudryavtsev Alexander V. Chertovich Darja V. Guseva Arkady D. Litmanovich 《Macromolecular Symposia》2007,254(1):188-195
Summary: Simple models are studied for better understanding of the early stages of interchange reactions in polymer blends. For a homogeneous blend of homopolymers A and B, parameters of copolymer AB formed at the reaction beginning are explicitly calculated. It is shown that the analysis of the copolymer composition can help to establish the prevailing interchange mechanism. For a bilayer blend of immiscible homopolymers A and B, the reactive compatibilization through interchange is studied by continual Monte Carlo modeling. The analysis of the local distribution in block length shows that the interdiffusion of blend components may start only after the formation of rather short copolymer blocks in the course of interchange. 相似文献
106.
107.
Analysis of the field dependence of the order parameters and comparison with experimental data on the behavior of the magnetic
characteristics of iron phosphide compounds in the stability region of the metamagnetic phase provides a basis for identifying
the type of magnetic structure that can exist in this case. The invariants responsible for first-order magnetic phase transitions
in crystals having a triangular magnetic structure are identified from the entire rational basis of invariants.
Fiz. Tverd. Tela (St. Petersburg) 39, 940–945 (May 1997) 相似文献
108.
A mechanism is proposed for the ionization of clusters evaporated from the surface of a metal subjected to fast-ion bombardment.
According to this mechanism, part of the internal energy of the cluster nuclei is transferred to its electronic subsystem,
with subsequent ionization. Within the framework of this approach, the dependence of the degree of ionization on n (the number of atoms in the cluster) is calculated for the evaporated clusters. The results obtained are in agreement with
experimental data.
Zh. Tekh. Fiz. 67, 1–5 (December 1997) 相似文献
109.
N. A. Medvedeva 《Russian Physics Journal》1995,38(9):978-982
110.