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31.
In order to determine the sufficient conditions for realization of oscillatory instability and the stages responsible for destabilization of the reaction regime in the potassium iodate-hydrogen peroxide-cysteine-sulfuric acid system, we have carried out bifurcation analysis of its mathematical model. We have determined the criteria for the appearance and size of the limit cycle in the phase space of the concentrations of the basic variables of the system; we have established the number and type of stability of the stationary states.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 667–673, November–December 1986. 相似文献
32.
Ya. T. Éidus N. I. Ershov T. V. Zueva S. D. Pirozhkov 《Russian Chemical Bulletin》1974,23(12):2758-2760
Conclusions The accelerating effects of carbon monoxide in the hydropolymerization of ethylene and propylene in the presence of Co-clay catalyst depend both on its concentration and the reaction temperature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2853–2855, December, 1974. 相似文献
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Aronica C Chastanet G Zueva E Borshch SA Clemente-Juan JM Luneau D 《Journal of the American Chemical Society》2008,130(7):2365-2371
A series of compounds (cat)[V6O6(OCH3)8(calix)(CH3OH)] was obtained under anaerobic conditions and solvothermal reaction of VOSO4 with p-tert-butylcalix[4]arene (calix) in methanol using different types of bases (Et4NOH, NH4OH, pyridine, Et3N). All compounds contain the same polyoxo(alkoxo)hexavanadate anion [V6O6(OCH3)8(calix)(CH3OH)]- (1) exhibiting a mixed valence {VIIIVIV5O19} core with the so-called Lindqvist structure coordinated to a calix[4]arene macrocycle and cocrystallizing with the conjugated acid of the base (cat = Et4N+, NH4(+), pyridinium, Et3NH+) involved in the synthesis process. The structures have been fully established from X-ray diffraction on single crystals and the mixed valence state has been confirmed by bond valence sum calculations. The magnetic behavior of all compounds are the same because of the polyalkoxohexavanadate anion [V6O6(OCH3)8(calix)(CH3OH)]- (1) and have been interpreted by DFT calculations. Thus the V(III)...V(IV) interactions are found to be weakly ferromagnetic (<5.5 cm(-1)) while the V(IV)...V(IV) are antiferromagnetic (-17.6; -67.6 cm(-1)). The set of the coupling exchange parameters allows a good agreement with the magnetic experimental data. 相似文献
35.
The effective self-diffusion coefficients of ions in premicellar and micellar solutions of sodium dodecyl sulfate are measured
by the NMR self-diffusion method at 40°C. The obtained regularities are explained using a proposed model that takes into account
the possible surface diffusion of counterions bound with micelles. This effect is shown to markedly influence the charge transfer
in micellar solutions. Based on the results obtained, the self-diffusion coefficients of bound Na+ counterions are estimated and the causes and ranges of their variations are indicated. 相似文献
36.
We consider a phenomenon of the Vavilov-Cherenkov type that can be observed in a space with a metal-dielectric boundary that
well reflects light. An electron that initially uniformly moves at a constant velocity near this boundary creates surface
plasmon-polaritons the phase velocity of which is lower than the electron velocity. The momentum of a photon in the created
plasmon-polariton is calculated. This momentum may be almost as high as the doubled initial electron momentum. The velocity
of the electron that created the photon in the plasmon-polariton may also become almost zero. We show that, at a nonzero temperature,
this process has a nonzero probability. 相似文献
37.
38.
Zueva O. S. Gubaidullin A. T. Makarova A. O. Bogdanova L. R. Zakharova L. Ya. Zuev Yu. F. 《Russian Chemical Bulletin》2020,69(3):581-589
Russian Chemical Bulletin - The structures of a protein-polysaccharide composite hydrogel and its modifications prepared using carbon nanotubes (CNTs) were studied by small-angle X-ray scattering... 相似文献
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Pichon C Dolbecq A Mialane P Marrot J Rivière E Goral M Zynek M McCormac T Borshch SA Zueva E Sécheresse F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(10):3189-3199
While the reaction of [PW(11)O(39)](7-) with first row transition-metal ions M(n+) under usual bench conditions only leads to monosubstituted {PW(11)O(39)M(H(2)O)} anions, we have shown that the use of this precursor under hydrothermal conditions allows the isolation of a family of novel polynuclear discrete magnetic polyoxometalates (POMs). The hybrid asymmetric [Fe(II)(bpy)(3)][PW(11)O(39)Fe(2) (III)(OH)(bpy)(2)]12 H(2)O (bpy=bipyridine) complex (1) contains the dinuclear {Fe(micro-O(W))(micro-OH)Fe} core in which one iron atom is coordinated to a monovacant POM, while the other is coordinated to two bipyridine ligands. Magnetic measurements indicate that the Fe(III) centers in complex 1 are weakly antiferromagnetically coupled (J=-11.2 cm(-1), H=-JS(1)S(2)) compared to other {Fe(micro-O)(micro-OH)Fe} systems. This is due to the long distances between the iron center embedded in the POM and the oxygen atom of the POM bridging the two magnetic centers, but also, as shown by DFT calculations, to the important mixing of bridging oxygen orbitals with orbitals of the POM tungsten atoms. The complexes [Hdmbpy](2)[Fe(II)(dmbpy)(3)](2)[(PW(11)O(39))(2)Fe(4) (III)O(2)(dmbpy)(4)]14 H(2)O (2) (dmbpy=5,5'-dimethyl-2,2'-bipyridine) and H(2)[Fe(II)(dmbpy)(3)](2)[(PW(11)O(39))(2)Fe(4) (III)O(2)(dmbpy)(4)]10 H(2)O (3) represent the first butterfly-like POM complexes. In these species, a tetranuclear Fe(III) complex is sandwiched between two lacunary polyoxotungstates that are pentacoordinated to two Fe(III) cations, the remaining paramagnetic centers each being coordinated to two dmbpy ligands. The best fit of the chi(M)T=f(T) curve leads to J(wb)=-59.6 cm(-1) and J(bb)=-10.2 cm(-1) (H=-J(wb)(S(1)S(2)+S(1)S(2*)+S(1*)S(2)+S(1*)S(2*))-J(bb)(S(2)S(2*))). While the J(bb) value is within the range of related exchange parameters previously reported for non-POM butterfly systems, the J(wb) constant is significantly lower. As for complex 1, this can be justified considering Fe(w)--O distances. Finally, in the absence of a coordinating ligand, the dimeric complex [N(CH(3))(4)](10)[(PW(11)O(39)Fe(III))(2)O]12 H(2)O (4) has been isolated. In this complex, the two single oxo-bridged Fe(III) centers are very strongly antiferromagnetically coupled (J=-211.7 cm(-1), H=-JS(1)S(2)). The electrochemical behavior of compound 1 both in dimethyl sulfoxide (DMSO) and in the solid state is also presented, while the electrochemical properties of complex 2, which is insoluble in common solvents, have been studied in the solid state. 相似文献