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601.
Ultrafast Decay Dynamics of N-Ethylpyrrole Excited to the S1 Electronic State: A Femtosecond Time-Resolved Photoelectron Imaging Study
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Wen-peng Yuan Bai-hui Feng Dong-yuan Yang Yan-jun Min Sheng-rui Yu Guo-rong Wu Xue-ming Yang 《化学物理学报(中文版)》2021,34(4):386-392
N-ethylpyrrole is one of ethyl-substituted derivatives of pyrrole and its excited-state decay dynamics has never been explored. In this work, we investigate ultrafast decay dynamics of N-ethylpyrrole excited to the S1 electronic state using a femtosecond time-resolved photoelectron imaging method. Two pump wavelengths of 241.9 and 237.7 nm are employed. At 241.9 nm, three time constants, 5.0±0.7 ps, 66.4±15.6 ps and 1.3±0.1 ns, are derived. For 237.7 nm, two time constants of 2.1±0.1 ps and 13.1±1.2 ps are derived. We assign all these time constants to be associated with different vibrational states in the S1 state. The possible decay mechanisms of different S1 vibrational states are briefly discussed. 相似文献
602.
《Chemical physics》1987,117(2):227-235
Time-resolved photoionization mass spectrometry in the millisecond range has been employed to study the reaction C6H5OCH+3 → C6H+6 + CH2O in anisole. Photoionization efficiency (PIE) curves gave a long-time limiting appearance energy value, AE = 10.85 ± 0.05 eV at 298 K. Experimental PIE curves and breakdown graphs at t = 6 μs and 2 ms were compared to those predicted by the statistical theory (RRKM/QET) and by previous photoelectron—photoion coincidence spectrometry results. A sensitivity analysis yielded the following activation parameters: critical energy of activation, E0 = 59.6 ± 0.6 kcal/mol, and entropy of activation, ΔS3(1000 K) = 7.25 ± 2.2 eu. 相似文献
603.
604.
《Chemical physics》1987,114(1):85-93
Three-dimensional quasiclassical trajectory calculations were carried out for the reaction of oxygen atoms O(3P) with hydrogen iodide molecules (HI and DI) for the temperature range 200–550 K, using a LEPS potential-energy surface. The calculated results include reaction cross sections, rate constants, kinetic isotope effects, the influence of vibrational and rotational excitation of the reactants on the dynamics, and the product energy partitioning and angular distribution. The calculated results are in good agreement with the available experimental results. The dynamics of the O + HI reaction is discussed in view of the associated mass combination H + LH′ (H and H′ are heavy atoms and L is a light atom), and in relation to earlier trajectory results for the reactions O + HCl and O + HBr. 相似文献
605.
QUAN Wei-long TANG Ping-ying TANG Bi-yu HAN Ke-li 《高等学校化学研究》2007,23(1):96-100
IntroductionA series of reactions of fluorine atoms with hydro-gen halidesF HCl HF Cl (1)(ΔH—00=-137·10 kJ/mol)F HBr HF Br (2)(ΔH—00=-202·73 kJ/mol)F HI HF I (3)(ΔH—00= -270·45 kJ/mol)belongs to the prototypical heavy-light-heavy reactionsa 相似文献
606.
S1 ← S0 laser excitation spectra of glyoxal in a supersonic jet: High-resolution rotational analysis
《Journal of Molecular Spectroscopy》1987,121(1):167-176
The high-resolution rotational spectra of several S1 ← S0 vibrational transitions of glyoxal are obtained and analyzed. Undispersed fluorescence excitation spectra are obtained with a CW ring dye laser in a supersonic jet, providing a linewidth down to 100 MHz. Rotational constants and band origins are determined with an asymmetric rotator program. Population distribution in the supersonic jet is studied. The overtones of the torsion mode (ν7) are examined as an approach to the trans-cis potential barrier. The 801 and 801 702 bands of A + B type, which are too congested at room temperature experiments, are well resolved in this jet experiment. As a result, the rotational constants obtained by fitting low-J and -K rotational transitions are in good agreement with the constants obtained by fitting large-J and -K transitions of room temperature spectra. Furthermore, on about 1000 analyzed lines no rotational perturbation has been observed. 相似文献
607.
608.
《Surface science》1995,341(3):L1072-L1077
The electronic structure of dissociatively chemisorbed nitrogen on Gd(0001) has been studied using angle-resolved photoemission at 150 K. The symmetry of the nitrogen-induced states and bonding configuration for the initial chemisorption has been identified. Bonding occurs above the Gd(0001) surface plane via the N pz orbital. Two possible adsorption sites are postulated, with preferential occupancy that is dependent upon coverage. 相似文献
609.
610.
The time-dependent wave packet method has been employed to calculate the state-to-state integral cross sections and differential cross sections (DCSs) for three initial states of the title reaction on the recently constructed neural network potential energy surface. It is found that the product HBr(\begin{document}$ v' $\end{document} = 2, 3, 4) states have the dominated population in the entire energy region considered here, indicating an inverted HBr vibrational state distribution. More than half of the available energy ends up as product internal motion, and most of which goes into the vibrational motion. Our calculations show that initial rotational excitation of Br\begin{document}$ _2 $\end{document} has little effect on the product ro-vibrational state distributions and DCSs of the reaction. While the initial vibrational excitation has some influences. The initial vibrational excitation to \begin{document}$ v_0 $\end{document} = 5 obviously enhance the product vibrational excitation in the low energy region. The DCSs for collision energy up to 0.5 eV at the ground and rotationally excited state are peaked in the backward direction, but the width of the angular distribution increases considerably with the increase of collision energy. For the vibrationally excited state, the DCSs are rather complicated with some strong forward scattering peaks for highly vibrationally excited products. 相似文献