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91.
Philip J. Morrison 《Physics letters. A》1980,80(5-6):383-386
The well-known Maxwell-Vlasov equations that describe a collisionless plasma are cast into hamiltonian form. The dynamical variables are the physical although noncanonical variables E, B and f. We present a Poisson bracket which acts on these variables and the energy functional to produce the equations of motion. 相似文献
92.
93.
S. Garpman I. Lindgren J. Lindgren J. Morrison 《Zeitschrift für Physik A Hadrons and Nuclei》1976,276(3):167-177
A non-relativistic perturbation method of Brueckner-Goldstone type is used to calculate the hyperfine interactions in the lowest2 S and2 P states of the Li-like systems, Li, Be+, B2+, C3+, N4+, O5+ and F6+. The effect of the polarization of the closed shell is treated to all orders of perturbation, while the correlation effect is calculated in the lowest order, i.e. in the third order of the perturbation expansion. Experimental data are at present available only for Li, Be+ and F6+, and the agreement with the calculated values is in these cases very good, usually within the experimental uncertainties. This implies that the predictions made in the remaining cases should be quite reliable, which may simplify the experimental determination of these quantities. Theoretical values are also given for the quadrupole interaction, which can be used to determine the nuclear quadrupole moments, when accurate experimental information becomes available. 相似文献
94.
Effects of cycloheximide on liquid-holding recovery from ultraviolet radiation damage in yeast cells
Abstract. The role of protein synthesis in liquid-holding recovery from ultra-violet radiation damage in synchronized Saccharomyces cerevisiae cells has been studied using cycloheximide as a specific inhibitor of cytoplasmic protein synthesis. Liquid-holding recovery from UV-induced budding delay is completed within a few hours and is not inhibited by the presence of cycloheximide. Liquid-holding recovery from lethal UV damage is unaffected by cycloheximide for liquid-holding times less than about 12 h. For longer times recovery is inhibited, with survival enhancement eliminated after about 48 h. Periods greater than 48 h of liquid-holding in the presence of cycloheximide result in survival less than that obtained with immediate plating, but the same concentration of cycloheximide is not toxic to unirradiated cells. 相似文献
95.
P. Bosetti M. Deutschmann H. Grässler G. Otter H.H. Seyfert K. Böckmann J. Hofmann J. Lowsky G. Zobernig V.T. Cocconi T. Coghen V. Karimäki G. Kellner D.R.O. Morrison J. Zaorska 《Nuclear Physics B》1975,94(1):21-38
The production of is measured in π+p reactions at 16 GeV/c. The total strange particle cross section is found to be 4.0 ± 0.3 mb, about 20% of the inelastic cross section. Cross sections for single strange particles and for strange particle pairs are determined, both inclusively and as functions of the charged multiplicity. Relative production rates for different strange particle combinations are compared with the prediction of the isospin statistical model. Inclusive spectra for single particles are studied and it is found the KS0 are produced mostly in the forward hemisphere, most probably by fragmentation of the incident pion into . The Λ are mostly backwards, probably deriving from fragmentation of the proton into ΛK pairs. The tend to be produced forwards, but evidence is found for central production. Distributions in rapidity of the Λ particles from π+p interactions are compared in terms of the factorisation hypothesis. Results are given on the Λ transversal polarisation. 相似文献
96.
M. Deutschmann R. Honecker K. Rumpf U. Kundt M. Walter U. Idschok R. Hartmann V.T. Cocconi T. Coghen S. Humble A. Kotański D.R.O. Morrison J. Figiel A. Guła P. Malecki B. Muryn L. Suszycki E. Leitner 《Nuclear Physics B》1975,85(1):31-38
The differential cross section for the charge-exchange process π+p → π0 (π+p) at 8, 16 and 23 GeV/c is presented for several regions of the π+p effective mass. It is found that the dip at t′ ≈ 0.6 (GeV/c)2 which is observed in the Δ(1236) mass band becomes a less pronounced structure in the higher mass regions. However, while the slope of the distributions in the near-forward direction decreases strongly with increasing π+p mass, there is no evidence that the observed structure moves to higher values of t′ as the π+p mass increases. These results are consistent with a Regge-exchange picture where the position of the dip is determined by the exchanged trajectory, but are inconsistent with a simple geometrical picture. 相似文献
97.
A many-body calculation of the hyperfine interaction in the lowest2S and2P states of li-like systems
S. Garpman I. Lindgren J. Lindgren J. Morrison 《Zeitschrift für Physik A Hadrons and Nuclei》1976,99(4):167-177
A non-relativistic perturbation method of Brueckner-Goldstone type is used to calculate the hyperfine interactions in the lowest2
S and2
P states of the Li-like systems, Li, Be+, B2+, C3+, N4+, O5+ and F6+. The effect of the polarization of the closed shell is treated to all orders of perturbation, while the correlation effect is calculated in the lowest order, i.e. in the third order of the perturbation expansion. Experimental data are at present available only for Li, Be+ and F6+, and the agreement with the calculated values is in these cases very good, usually within the experimental uncertainties. This implies that the predictions made in the remaining cases should be quite reliable, which may simplify the experimental determination of these quantities. Theoretical values are also given for the quadrupole interaction, which can be used to determine the nuclear quadrupole moments, when accurate experimental information becomes available. 相似文献
98.
H. Gr?ssler D. Lanske R. Schulte G.T. Jones R.P. Middleton S.W. ONeale K. B?ckmann W. Gebel C. Geich-Gimbel B. Nellen A. Grant H. Klein D.R.O. Morrison P. Schmid H. Wachsmuth J.S. Chima M.M. Mobayyen J. Wells 《Nuclear Physics B》1983,223(2):269-295
In an experiment with the hydrogen bubble chamber BEBC at CERN multiplicities of hadrons produced in νp and interactions have been investigated. Results are presented on the multiplicities of charged hadrons and neutral pions, forward and backward multiplicities of charged hadrons and correlations between forward and backward multiplicities. Comparisons are made with hadronic reactions and e+e? annihilation. In the framework of the quark-parton model the data imply similar charged multiplicities for the fragments of a u- and a d-quark, and a larger multiplicities for the fragments of a uu- than for a ud-diquark. The correlation data suggest independent fragmentation of the quark and diquark for hadronic masses above ~ 7 GeV and local charge compensation within an event. 相似文献
99.
100.
Rollin J. Morrison 《Nuclear Physics B》1977,121(2):277-284
Using the simple quark parton model, estimates for the three-photon structure function, V(x), of the proton are given. This function, which is proportional to the interference between inelastic Compton scattering and wide angle bremsstrahlung, is shown to have an upper bound of . Using SLAC inelastic electron scattering data from the proton this implies that V(x) is not dominated by a quasielastic peak, and therefore the sum rule, , will be difficult to check at SLAC energies. Using electron scattering data from both the neutron and the proton, a more restrictive upper limit on V(x) is given which, at intermediate and large values of x, is nearly the same as values determined from two different sets of quark distributions. We conclude that the experiment still provides a new test of the proton model and a method for determining the quark charge. 相似文献