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81.
We review experimental and theoretical studies devoted to extract information on the behaviour of the symmetry energy, in
density regions different from the normal value, with charge-asymmetric reactions at Fermi energies. In particular, we focus
on the analysis of fragmentation reactions and isotopic properties of the reaction products. Results concerning “isoscaling”
properties and the N/Z equilibration among the reaction partners in semi-peripheral reactions are also discussed. 相似文献
82.
A. Miller D. A. B. Miller M. Bensoussan J. M. Moison D. C. Haueisen D. A. Depatie P. W. Kruse M. A. Khan A. L. Smirl B. S. Wherrett T. F. Boggess G. P. Perryman D. S. Chemla P. W. Smith A. C. Gossard W. T. Tsang S. Chu P. Hu T. M. Jedju S. Y. Yuen P. A. Wolff V. Moloney F. A. Hopf H. M. Gibbs S. L. McCall D. L. Kaplan S. Ovadia J. V. Moloney D. F. Walls 《Applied physics. B, Lasers and optics》1982,28(2-3):92-101
83.
84.
Wing Tsang 《国际化学动力学杂志》1976,8(2):193-203
The life times of chemically activated alcohols have been determined using the high-pressure unimolecular rate parameters for thermal decomposition of alcohols from shocktube studies and RRKM calculations. They are compared with literature numbers (from insertion of 0(1D) into hydrocarbons). It is suggested that in some cases singlet oxygen carries excess energy into the hydrocarbon. The consequences of such an assumption are explored and discrepancies with previously published conclusions discussed. 相似文献
85.
Wing Tsang 《国际化学动力学杂志》1969,1(2):245-278
Several hydrocarbons have been pyrolyzed in a single pulse shock tube. Rate parameters for the main bond breaking step have been found to be In combination with similar studies carried out earlier and through application of the well-established experimental rule (k(AB)/kr(AA)kr(BB))1/2 ~ 2 where A and B are radicals and the rate constants are for the combination of these radicals, rate parameters for the thermal decomposition of all the hydrocarbons formed from any pair of the following radicals: methyl, ethyl, isopropyl, t-butyl, t-amyl, allyl, methylallyl, and benzyl have been calculated. The available calculated and experimental values of the decomposition rate constants are in excellent agreement. It appears that, with the possible exception of reactions involving the ejection of methyl radicals, the frequency factors per bond are nearly constant, depending only upon the type of carbon–carbon bond that is being broken. These values are all lower than those expected from the radical recombination rates. Heats of formation of ethyl, t-amyl, benzyl, methylallyl, n-propyl, s-butyl, isobutyl, neopentyl, and 3-pentyl radicals have been derived. Rate parameters for the decomposition of some simple ketones and ethers have also been estimated. 相似文献
86.
Bert Fraser-Reid Deen B. Tulshian Ray Tsang Derek Lowe Vernon G.S. Box 《Tetrahedron letters》1984,25(41):4579-4582
Structurally equivalent derivatives of pyranosides and cyclohexanes undergo the spiro-Claisen rearrangement with different stereochemical results. A rationalization for the course observed with the pyranosides is suggested, which invokes interaction of the oxygen lone pair with a (developing) electron deficient centre at the spiro carbon. 相似文献
87.
The Raman spectra of intercalated 1TTaS2 and 2HTaSe2 have been measured for the first time. Normal symmetry allowed optic phonons and charge density wave induced modes are observed in both systems. The spectra of the ethylenediamine intercalated compounds are qualitatively similar to those of the pure materials with small quantitative shifts in frequency and changes in the relative intensities of the CDW induced modes. The qualitative similarities in the spectra of the pure and the intercalated compounds reflect the two dimensional character of these materials and show that the dynamic properties of the charge density wave states are largely determined by intralayer effects. 相似文献
88.
89.
E. Tsang K. Baberschke J. Kästner B. J. Beaudry 《Zeitschrift für Physik B Condensed Matter》1980,38(3):235-242
A logarithmical decrease in the resistivity below 10 K has been observed for 200 to 5,000 ppm Gd in Y and Sc. The decrease scales with the Gd concentration. The results are in line with previously published data forLu: Gd and LaAl2: Gd, they are discussed in terms of a ferromagnetic (J>0) Kondoeffect. The scaling parameterT
K
, and the extracted effective change interactionJ
eff
are compared with other experimental results. In addition the negative magnetoresistance (the freezing out of spin-disorder scattering) has been measured up to 50 kG. Possible interference of potential and exchange scattering may have been observed in the magnetoresistance.Supported by special research fund Sfb 161 of the Deutsche Forschungsgemeinschaft 相似文献
90.
Wing Tsang 《国际化学动力学杂志》1978,10(7):687-711
4-Methylhexyne-1, 5-methylhexyne-1, hexyne-1, and 6-methylheptyne-2 have been decomposed in comparative-rate single-pulse shock-tube experiments. Rate expressions for the initial decomposition reactions at 1100°K and from 2 to 6 atm pressure are In combination with previous results, rate expressions for propargyl C? C bond cleavage are related to that for the alkanes by the expression These results yield a propargyl resonance energy of D(nC3H7-H) – D(C3H3-H) = 36 ± 2 kJ, in excellent agreement with a previous shock-tube study. They also lead to D(CH3C≡CCH2-H) – D(C3H3-H) = 0.6 ± 3 kJ, D(sC4H9-H) – D(iC3H7-H) = 0 ± 3 kJ, D(iC4H9-H) – D(nC3H7-H) = 2 ± 3 kJ, and D(nC3H7-H) – D(iC3H7-H) = 13.9 ± 3 kJ (all values are for 300°K). The systematics of the molecular decomposition process are explored. 相似文献