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181.
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183.
P.M. Bird A.S. Clough K.R. Parker G.J. Pyle G.T.A. Squier S. Baird C.J. Batty A.I. Kilvington F.M. Russell P. Sharman 《Nuclear Physics A》1983,404(3):482-494
The X-ray spectrum obtained with kaons stopping in liquid hydrogen has been measured. Possible candidates for X-ray lines from kaonic hydrogen atoms have been identified and the results compared with previous experiments and with theoretical predictions. X-ray lines from σ?p atoms may also have been observed. 相似文献
184.
The phenomenon of giant intrinsic magnetic hardness is investigated in compounds R1−x
Sm
x
Co2Ni3 with R=Y, Pr, Gd, Tb, Er. Partial Er substitution for Sm actually increases magnetic hardness while all other substitutions
decrease magnetic hardness. The strength of coercivity is thus dependent on both the sign and magnitude of the crystal field
interaction. The temperature dependence of coercivity is complex in the case of Pr substitution as a result of competing effects
from thermal activation and a decrease in anisotropy at low temperatures.
This study has been supported by a grant from the National Science Foundation. 相似文献
185.
186.
Senanayake K Thompson AL Howard JA Botta M Parker D 《Dalton transactions (Cambridge, England : 2003)》2006,(45):5423-5428
The macrocyclic ligand 1,4,7,10-tetraazacyclododecane-1,4,7-triyl(methylenebenzyl-phosphinic acid) H3L3, has been prepared and its complexes with Eu, Gd and Tb(III) studied by NMR, relaxometry, luminescence and single crystal X-ray crystallography. In solution and in the crystal, the complexes have eight-coordinate metal centres with bridging phosphinate groups linking the two twisted square antiprismatic coordination polyhedra. A single stereoisomer crystallises from solution with an RRR and SSS configuration at the P centres in each sub-unit. The relaxivity of [GdL3]2 is low (1.9 mM-1 s-1, 298 K, 20 MHz), consistent with the absence of any proximate water molecules. The terbium dimer possesses a relatively long excited state lifetime (2.47 ms, 298 K). 相似文献
187.
We have calculated the stability of two of the low-index surfaces known to dominate the morphology of ZnO as a function of stoichiometry. These two surfaces are (10(-)10) and (11(-)20). In each case, two terminations only are stable for a significant range of oxygen and hydrogen chemical potential: the pure stoichiometric surface and a surface covered in a monolayer of water. The mode by which the water adsorbs is however different for the two surfaces considered. On the (10(-)10) surface the close proximity of the water molecules means hydrogen bonding can occur between adjacent chemiabsorbed water molecules and hence there is little difference in the stability of the hydrated and hydroxylated surface, and in fact the most stable surface occurs with a combination of dissociated and undissociated water adsorption. In the case of the (11(-)20) surface, it is only when full dissociation has occurred that a hydrogen-bonding network can form. Our results also show good agreement between DFT and atomistic simulations, suggesting that potential based methods can usefully be applied to ZnO. 相似文献
188.
Ashfold MN Nahler NH Orr-Ewing AJ Vieuxmaire OP Toomes RL Kitsopoulos TN Garcia IA Chestakov DA Wu SM Parker DH 《Physical chemistry chemical physics : PCCP》2006,8(1):26-53
Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics. 相似文献
189.
First principles calculations using density functional theory with corrections for on-site Coulomb interactions (DFT + U) are presented in which we compute the energy for the conversion of CO to CO(2), NO(2) to NO and NO to N(2) over ceria surfaces. The surface sensitivity is discussed on the basis of the vacancy formation energies. 相似文献
190.
Vibrational spectroscopy of N-phenylmaleimide 总被引:1,自引:0,他引:1
A combination of infrared, Raman and inelastic neutron scattering (INS) spectroscopies with density functional theory (DFT) calculations is used to provide a complete assignment of the vibrational spectra of N-phenylmaleimide and N-(perdeuterophenyl)maleimide. DFT is shown to give very good results for the frequencies and atomic displacements in the modes. These are used to generate INS spectra which are excellent agreement with the observed. The calculated infrared and Raman spectra are much less reliable, although this may be more of a presentation problem than a real failing. 相似文献