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61.
Christian Svendsen O. Sonnich Mortensen Niels E. Henriksen 《Chemical physics letters》1996,260(5-6):627-632
Time-dependent recursion relationships are derived for optical absorption and resonance Raman correlators in the multidimensional harmonic case using a second-quantization formalism. Furthermore, a procedure is given for the calculation of correlators involving a general analytic coordinate dependence of the transition dipole moment. 相似文献
62.
Thormod Henriksen Arne Dahlback Søren H.H. Larsen Johan Moan 《Photochemistry and photobiology》1990,51(5):579-582
The effect of changes in the ozone layer on the incidence of skin cancer was explored using data for Norway. Attempts were made to arrive at a relationship between the "environmental effective UV-dose" and the skin cancer incidence. Norway is well suited for this purpose because of the large variation in the annual UV-dose from north to south. Furthermore we have a well developed cancer registry and a homogeneous population with regard to skin type. Four different regions of the country, each with a broadness of 1 degree in latitude (approximately 111 km), were selected (located around 69.5, 63.5, 60 and 58.5 degrees N). The annual effective UV-doses for these regions were calculated, assuming normal ozone conditions throughout the year and the action spectrum proposed by CIE, which extends up to 400 nm. The incidence rate (in the period 1970-1980) of malignant melanoma and non-melanoma skin cancer (mainly basal cell carcinoma) increased with the annual environmental UV-doses. For both these types of cancer a quadratic dose-effect relationship seems to be valid to a first approximation. The present data indicate that the incidence of skin cancer would increase by approximately 2% for each percent ozone reduction. 相似文献
63.
Within the B? absorption band of CH(2)BrCl, we theoretically analyze the laser-induced control of the Br/Cl branching ratio, Br + CH(2)Cl ← CH(2)BrCl → CH(2)Br + Cl, with CH(2)BrCl initially in its vibrational ground state. For weak-field excitation, the Br/Cl branching ratio increases as a function of wavelength, however, for wavelengths below 180 nm the branching ratio cannot be made smaller than 0.4. Using optimal control theory, we show that the branching ratio can be made significantly less than 0.4, only when very strong fields are employed. Thus, the present work strongly suggests that a Tannor-Rice type laser control mechanism for selective bond breakage in CH(2)BrCl cannot take place without accompanying photoionization. 相似文献
64.
Daniel?Henriksen Tom?Kim Ionel??ifreaEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(1):17
We studied the influence of the nuclear spin diffusion on the dynamical nuclear polarization of low dimensional nanostructures subject to optical pumping. Our analysis shows that the induced nuclear spin polarization in semiconductor nanostructures will develop both a time and position dependence due to a nonuniform hyperfine interaction as a result of the geometrical confinement provided by the system. In particular, for the case of semiconductor quantum wells, nuclear spin diffusion is responsible for a nonzero nuclear spin polarization in the quantum well barriers. As an example we considered a 57 Å GaAs square quantum well and a 1000 Å Al x Ga1?x As parabolic quantum well both within 500 Å Al0.4Ga0.6As barriers. We found that the average nuclear spin polarization in the quantum well barriers depends on the strength of the geometrical confinement provided by the structure and is characterized by a saturation time of the order of few hundred seconds. Depending on the value of the nuclear spin diffusion constant, the average nuclear spin polarization in the quantum well barriers can get as high as 70% for the square quantum well and 40% for the parabolic quantum well. These results should be relevant for both time resolved Faraday rotation and optical nuclear magnetic resonance experimental techniques. 相似文献
65.
E.A. Henriksen S. Syed Y.J. Wang M.J. Manfra L.N. Pfeiffer K.W. West H.L. Stormer 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):318
A large splitting of the cyclotron resonance line, observed in two different two-dimensional electron systems, remains unexplained. The splitting resembles an anti-level crossing with an unidentified mode of the semiconductor system. Here, we review our data on this splitting, and highlight some results of recent experiments. 相似文献
66.
Christian Henriksen 《Transactions of the American Mathematical Society》2003,355(9):3625-3639
We show that there exist two cubic polynomials with connected Julia sets which are combinatorially equivalent but not topologically conjugate on their Julia sets. This disproves a conjecture by McMullen from 1995.
67.
68.
Localized water suppressed proton spectroscopy has opened up a new field of pathophysiological studies of severe brain ischemia. The signals obtained with the pulse sequences used so far are both T1 and T2 weighted. In order to evaluate the extent to which changes in metabolite signals during the course of infarction can be explained by changes in T1 and T2 relaxation times, eight patients with acute stroke were studied. STEAM sequences with varying echo delay times and repetition times were used to measure T1 and T2 of N-acetyl-aspartate (NAA), creatine plus phosphocreatine (Cr+PCr) and choline containing compounds (CHO) in a 27-ml voxel located in the affected area of the brain. Ten healthy volunteers served as controls. We found no difference in T1 or T2 of the metabolites between the patients and the normal controls. The T2 of CHO was longer than that of NAA and Cr+PCr. Our results indicate that spectra obtained in brain infarcts and normal tissue with the same acquisition parameters are directly comparable with respect to relative signal intensities as well as signals scaled with internal and external standards. 相似文献
69.
Rizzi Andrea Jensen Travis Slochower David R. Aldeghi Matteo Gapsys Vytautas Ntekoumes Dimitris Bosisio Stefano Papadourakis Michail Henriksen Niel M. de Groot Bert L. Cournia Zoe Dickson Alex Michel Julien Gilson Michael K. Shirts Michael R. Mobley David L. Chodera John D. 《Journal of computer-aided molecular design》2020,34(5):601-633
Journal of Computer-Aided Molecular Design - Approaches for computing small molecule binding free energies based on molecular simulations are now regularly being employed by academic and industry... 相似文献
70.
Henriksen EA Jiang Z Tung LC Schwartz ME Takita M Wang YJ Kim P Stormer HL 《Physical review letters》2008,100(8):087403
We present the first measurements of cyclotron resonance of electrons and holes in bilayer graphene. In magnetic fields up to B=18 T, we observe four distinct intraband transitions in both the conduction and valence bands. The transition energies are roughly linear in B between the lowest Landau levels, whereas they follow square root[B] for the higher transitions. This highly unusual behavior represents a change from a parabolic to a linear energy dispersion. The density of states derived from our data generally agrees with the existing lowest order tight binding calculation for bilayer graphene. However, in comparing data to theory, a single set of fitting parameters fails to describe the experimental results. 相似文献