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61.
OK Yoon WG Hwang JC Choe MS Kim 《Rapid communications in mass spectrometry : RCM》1999,13(14):1515-1521
A technique to investigate photodissociation kinetics on a nanosecond time scale has been devised for molecular ions generated by multiphoton ionization (MPI) using mass-analyzed ion kinetic energy spectrometry. The branching ratio or rate constant has been determined for the photodissociation of the n-butylbenzene, bromobenzene, iodobenzene, and aniline molecular ions generated by MPI at 266 nm. The ion internal energies have been estimated by comparing the measured kinetic data with the previous energy dependence data. The analysis has shown that only those molecular ions generated by two-photon ionization contribute to the photodissociation signals. Around half of the available energy has been found to remain as molecular ion internal energy in the two-photon ionization process. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
62.
Magnetic resonance of congenital anorectal malformations 总被引:1,自引:0,他引:1
63.
Laterally resolved measurements of the quantum size effect (QSE) in electron reflectivity are made with low energy electron microscopy on coherently strained Ag films on a W(110) surface. The evolution of the total film thickness with increasing number of atomic layers is determined accurately by dynamical theory analysis of the QSE features. Combined with a model of layer spacings obtained from first-principles calculations, this provides for a novel approach to determine the buried interface layer spacing, which is inaccessible to other methods. 相似文献
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Following a suggestion by Orzel et al. [Science 291, 2386 (2001)]], we analyze bosons in an optical lattice undergoing a sudden parameter change from the Mott to superfluid phase. We introduce a modified coherent states path integral to describe both phases. The saddle point theory yields collective oscillations of the uniform superfluid order parameter. We calculate its damping rate by phason pair emission. In two dimensions the overdamped region largely overlaps with the quantum critical region. Measurements of critical dynamics on the Mott side are proposed. 相似文献
68.
Marvin Cummings Sebastian Gliga Boris Lukanov Eric I. Altman Matthias Bode Enrique V. Barrera 《Surface science》2011,605(1-2):72-80
Here, the interactions of C60 at the surface of pseudomorphic Ni/Cu(100) and Co/Ru(0001) thin films and its effect on film growth and morphology were determined using in-situ scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). The novel development of C60-metallic based nanosystems, such as C60 molecular junction transistors, hinges on our ability to understand the factors governing structural stability in these nanosystems and the nature of the bond interactions at the C60–metal interface. In this study, C60 deposited onto the Ni(100) film surface is observed to be fairly immobile and uniformly distributed across the Ni surface. On the Co(0001) film surface however, C60 mobility is observed to be severely limited in some regions and highly mobile in others dependent upon Co film surface reconstruction, resulting in a non-uniform distribution of C60 across the Co film surface. Despite the presence of C60 on the Ni surface, there is no obvious influence of the C60 on further Ni film growth. In contrast, during Co film growth, islands only nucleate and grow from step edges or locally around C60 molecules. The strength of the Co–C60 bond interaction appears stronger than the Co–Co bond on Co film terrace. Generally, the Ni and Co films both continue epitaxial film growth in the presence of molecular C60. AES results indicate the C60 molecules maintain their chemical integrity during growth. 相似文献
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Scott C. Coste Tyler J. Pearson Alison B. Altman Ryan A. Klein Brian A. Finney Michael Y. Hu E. Ercan Alp Bess Vlaisavljevich Danna E. Freedman 《Chemical science》2020,11(36):9971
The spin state in heterobimetallic complexes heavily influences both reactivity and magnetism. Exerting control over spin states in main group-based heterobimetallics requires a different approach as the orbital interactions can differ substantially from that of classic coordination complexes. By deliberately engendering an energetic mismatch within the two metals in a bimetallic complex we can mimic the electronic structure of lanthanides. Towards this end, we report a new family of complexes, [Ph,MeTpMSnPh3] where M = Mn (3), Fe (4), Co (5), Ni (6), Zn (7), featuring unsupported bonding between a transition metal and Sn which represent an unusual high spin electronic structure. Analysis of the frontier orbitals reveal the desired orbital mismatch with Sn 5s/5p primarily interacting with 4s/4p M orbitals yielding localized, non-bonding d orbitals. This approach offers a mechanism to design and control spin states in bimetallic complexes.We report a series of high spin bimetallic transition metal–tin complexes. The unusual high spin configuration in a bimetallic complex is enabled by an energetic mismatch in the orbital energies, leading to lanthanide-like nonbonding interactions. 相似文献