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81.
The ν1 and ν3 bands of the NH2 radical were detected in absorption in the 2.9- to 3.2-μm region using a tunable difference frequency laser and a long-path Zeeman-modulated discharge cell. About 100 rotation-vibration transitions were measured and a simultaneous analysis of the Coriolis-coupled ν1 and ν3 states was made. It was found that the ν1 band is considerably stronger than ν3, in contrast to the similar molecule H2O. These results may prove useful in a search for interstellar NH2 by means of its rotation-vibration spectrum. 相似文献
82.
Konrad Grob Maurus Biedermann Konrad Bernath Hans-Peter Neukom Mario Galli 《Journal of separation science》1992,15(9):613-614
Recently introduced fused silica, primarily of the high temperature type, no longer allows the formation of a reliable press-fit seal. Attempts to tighten the connection with various kinds of glue proved unsatisfactory. Manufacturers of fused silica tubing are urged to devote more attention to the problem. 相似文献
83.
A detailed analysis of the high-resolution infrared emission spectra of gaseous HgH2 and HgD2 in the 1200-2200 cm(-1) spectral range is presented. The nu3 antisymmetric stretching fundamental bands of 204HgH2, 202HgH2, 201HgH2, 200HgH2, 199HgH2, 198HgH2, 204HgD2, 202HgD2, 201HgD2, 200HgD2, 199HgD2, and 198HgD2, as well as a few hot bands involving nu1, nu2, and nu3 were analyzed rotationally, and spectroscopic constants were obtained. Using the rotational constants of the 000, 100, 01(1)0, and 001 vibrational levels, we determined the equilibrium rotational constants (B(e)) of the most abundant isotopologues, 202HgH2 and 202HgD2, to be 3.135325(24) cm(-1) and 1.569037(16) cm(-1), respectively, and the associated equilibrium Hg-H and Hg-D internuclear distances (re) are 1.63324(1) A and 1.63315(1) A, respectively. The re distances of 202HgH2 and 202HgD2 differ by about 0.005%, which can be attributed to the breakdown of the Born-Oppenheimer approximation. 相似文献
84.
Sheridan PM Dick MJ Wang JG Bernath PF 《The journal of physical chemistry. A》2005,109(46):10547-10553
High-resolution spectra of the ~B(2)A(1)-- ~X(2)A(1) transitions of CaCH(3) and SrCH(3) have been recorded in a molecular jet/laser ablation source using laser excitation spectroscopy. Transitions arising from the K = 0 and 1 sub-bands have been observed for both molecules. An analysis of the data using a (2)A(1) symmetric top Hamiltonian has determined rotational and spin-rotation constants for the ~B(2)A(1) state of each molecule. From the rotational constants, structures have been estimated for both CaCH(3) and SrCH(3). The spin-rotation constant, epsilon(bc) = (epsilon(bb) + epsilon(cc))/2, in the ~B(2)A(1) state for both molecules is in reasonable agreement with the value calculated using the pure precession approximation. For CaCH(3), the K' = 1 levels of the ~B(2)A(1) state exhibit a perturbation that interchanges the energy ordering of the spin-rotation components. 相似文献
85.
The vibration-rotation emission spectra of CdH2 and CdD2 molecules have been recorded at high resolution using a Fourier-transform spectrometer. The molecules were generated in a furnace-discharge emission source by reaction of cadmium vapor with molecular hydrogen or deuterium. The fundamental bands for the antisymmetric stretching mode (upsilon3) of CdH2 and CdD2 were detected at about 1771.5 and 1278.3 cm(-1), respectively. In addition, the 002(sigma(g)+)-001(sigma(u)+) and 01 l(pi(g))-010(pi(u)) hot bands were observed for CdH2. Spectroscopic constants were determined for each of the 12 observed isotopologs: 110CdH2, 111CdH2, 112CdH2, 113CdH2, 114CdH2, 116CdH2, 1l0CdD2, 111CdD2, 112CdD2, 113CdD2, 114CdD2, and 116CdD2. The average Cd-H and Cd-D bond distances (r0) were determined to be 1.683028(10) and 1.679161(16) angstroms, respectively. 相似文献
86.
The emission spectrum of the NiF radical has been recorded by high-resolution Fourier transform spectroscopy in the region 6000-12 000 cm−1. Numerous new near-infrared bands were observed. In this paper three electronic transitions are analyzed leading to the identification of two new electronic states: a [12.0]2Φ7/2 state and a [11.1]2Π3/2 state located, respectively, at 12 008.89 and 11 096.05 cm−1 above the X2Π3/2 ground state. These electronic states can be correlated to the [3d8(3F)4s]2F atomic term of Ni+ as predicted by Carette et al. [J. Mol. Spectrosc.161, 323-335 (1993)]. 相似文献
87.
T. HiraoP.F. Bernath C.E. FellowsR.F. Gutterres M. Vervloet 《Journal of Molecular Spectroscopy》2002,212(1):53-56
The A2Π-X2Σ+ emission band system of the MgCl molecule has been studied by means of high-resolution Fourier transform spectroscopy. Excited MgCl molecules were produced by two different techniques: (i) at Orsay, they were created by mixing Mg vapor with a flow of He/Cl2 and excited in a “heated” Schüller-type discharge tube, and (ii) at Waterloo, they were generated by using a copper hollow cathode lamp loaded with MgCl2 powder. Rovibronic analysis of the (0, 0) and (0, 1) bands was performed. Molecular constants were derived in a weighted nonlinear least squares fit, including both the new line positions and the previously published microwave frequencies (M. Bogey, C. Demuynck, and J. L. Destombes, Chem. Phys. Lett.155, 265 (1989); Y. Ohshima and Y. Endo, Chem. Phys. Lett.213, 95 (1993)). 相似文献
88.
The emission spectra of TaN have been investigated in the region 3000-35 000 cm−1 using a Fourier transform spectrometer. The spectra were observed in a tantalum hollow-cathode lamp by discharging a mixture of 1.5 Torr of Ne and about 6 mTorr of N2. In addition to previously known bands, numerous additional bands were observed and assigned to a number of new transitions. The spectroscopic properties of the low-lying electronic states of TaN were also predicted by ab initio calculations. A 1Σ+ state, with equilibrium constants of Be=0.457 852 1(48) cm−1, αe=0.002 235 9(67) cm−1, and Re=1.683 099 9(88) Å, has been identified as the ground state of TaN based on our experimental observations supported by the ab initio results. The first excited state has been identified as the a3Δ1 spin component at 2827 cm−1 above the ground state. To higher energies, the states become difficult to assign because of their Hund's case (c) behavior and extensive interactions between the spin components of the electronic terms. 相似文献
89.
90.
The A 2Π-X2∑+ 0-0 transition of CaF has been examined by the technique of intermodulated fluorescence spectroscopy (“Lamb dip”). The hyperfine structure due to 19F and the spin-rotation fine structure of the X 2∑+ state was determined. Parameter values of b = 104.0 (9) MHz, c = 58(6) MHz and γ = 38.6(2) MHz were found for v = 0 of X2∑+ 相似文献