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71.
L. T. Zhuravlev 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):15-25
A short survey is presented of results on the dehydration, dehydroxylation and rehydroxylation of the surface of amorphous silica. 相似文献
72.
The exact solutions of the Einstein equations that correspond to a given evolution of the scale factor in the inflationary
stage in the development of the universe are considered within the framework of the theory of a self-acting scalar field that
interacts minimally with a gravitational field. The form of the potential that ensures a given rate of expansion and the solution
for the scalar field are calculated for each type of inflation considered. Some general laws of the relation between the form
of potential and the scale factor evolution are analyzed.
Moscow State University Branch in Ul'yanovsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 83–88,
August, 1996. 相似文献
73.
74.
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76.
77.
Yu. N. Zhuravlev N. G. Kravchenko O. S. Obolonskaya 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(1):20-28
Crystalline phase total energies, band structures, the distributions of the total and partial densities of electron states,
and atomic charges were calculated for lithium, sodium, and potassium oxides, peroxides, superoxides, and ozonides using the
CRYSTAL 06 and GAMESS packages in the B3LYP parameterization. For the molecular phases, the geometry was optimized and molecular
orbital energies calculated. The results obtained for metal oxides were compared with the experimental photoelectron spectroscopy
data and used to analyze their formation and thermal decomposition. 相似文献
78.
B. V. Zhuravlev A. A. Lychagin N. N. Titarenko V. G. Demenkov V. I. Trykova 《Physics of Atomic Nuclei》2010,73(7):1111-1115
The spectra of neutrons from the (p, n) reactions on the 208Pb and 209Bi nuclei were measured in the proton-energy range 8–11 MeV. These measurements were performed by using a time-of-flight spectrometer
of fast neutrons on the basis of the pulsed tandem accelerator EGP-15 of the Institute of Physics and Power Engineering (Obninsk,
Russian Federation). A high resolution and stability of the time-of-flight spectrometermade it possible to identify reliably
low-lying discrete levels alongwith the continuum section of the neutron spectra. The measured data were analyzed on the basis
of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed
by using the precise formalism of Hauser-Feshbach statistical theory together with the generalizedmodel of a superfluid nucleus
and the back-shifted Fermi gas model for the nuclear-level density. The nuclear-level densities in 208Bi and 209Po were determined along with their energy dependences and model parameters. Our results are discussed together with available
experimental data and recommendations of model systematics. 相似文献
79.
Microphotoluminescence from GaN/AlN quantum dots grown by molecular beam epitaxy on sapphire substrates along the (0001) axis
has been studied. To produce quantum dots of different average sizes and densities, the nominal amount of deposited GaN has
been varied from 1 to 4 ML. The density of the quantum dots was about 1011 cm−2, which corresponded to about 103 quantum dots excited in the experiments. The photo-luminescence from the quantum dots was linearly polarized and the maximum
polarization degree (15%) has been observed for the sample with the lowest amount of deposited GaN. The photoluminescence
intensity from this sample under continuous laser excitation decreased by more than two orders of magnitude for about 30 min
and then stabilized. The photoluminescence intensity from other samples under continuous excitation remained constant. We
suggest that a rather high polarization degree is caused by anisotropy in the strain and shape of the quantum dots formed
near the dislocations, which also act as the centers of nonradiative recombination. 相似文献
80.
A series of compounds Ln(RCOO)3·Phen (Ln=Eu, Gd, Tb; RCOO−-1- and 2-naphthoate, 1- and 2-naphthylacetate, 1- and 2-naphthoxyacetate anions, Phen-1,10-phenanthroline) was investigated by methods of optical spectroscopy. Compounds of composition Ln(RCOO)3·nH2O with the same carboxylate ligands are also considered. Results of studies of the effects of methylene spacer decoupling the π-π- or p-π-conjugation in the naphthylcarboxylate ligand on the structure of Eu3+ coordination centre, on the lifetime of 5D0 (Eu3+) state, and on processes of the excitation energy transfer to Eu3+ or Tb3+ ions are presented. Introduction of the methylene bridge in the ligand weakens the influence of the steric hindrances in forming of a crystal lattice and results in lowering the distortion of the Eu3+ luminescence centre, and in elongation of the observed 5D0 lifetime τobs. The latter is caused by decrease in contribution of the radiative processes rate 1/τr. This is confirmed by the correlation between the lifetimes τobs and the quantities “τr·const” inversely proportional to the total integral intensities of Eu(RCOO)3·Phen luminescence spectra. The methylene spacer performs a role of regulator of sensitization of the Ln3+ luminescence efficiency by means of an influence on mutual location of lowest triplet states of the ligands, the ligand-metal charge transfer (LMCT) states, and the emitting states of Ln3+ ions. The lowest triplet state in lanthanide naphthylcarboxylate adducts with Phen is related to carboxylate anion. A presence of the methylene spacer in naphthylcarboxylate ligand increases the triplet state energy. At the same time, the energy of “carboxylic group-Eu3+ ion” charge transfer states falls, which can promote the degradation of excitation energy. In naphthylcarboxylates investigated a range of the carboxylate triplet state energies from 19 150 to 20 600 cm−1 was demonstrated in dependence on the type of the carboxylate anion. The interligand energy transfer from Phen to carboxylate lowest triplet state was revealed in complexes with Phen ligand. The effect of OH-group inserted in 1- or 3-position of 2-naphthoate ligand on the excitation energy transfer is also analyzed. 相似文献