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111.
非晶合金剪切带动力学行为研究 总被引:5,自引:4,他引:1
剪切带是一种材料塑性变形高度局域化的变形模式, 广泛存在于非晶体系的形变中, 控制着这些无序体系失稳、灾难性断裂行为.传统的非晶体系如岩石, 胶体, 玻璃和聚合物等因较差的力学性能以及过于复杂的结构而不利于剪切带的实验研究. 近几十年来, 非晶合金的出现极大丰富了剪切带的研究, 推进了对剪切带的认识. 通过大量非晶合金中剪切带的实验和理论研究, 人们发现剪切带行为具有空间不均匀性和时间不连续性的特征, 表现出复杂的动力学特征, 和自然界以及物理系统中许多复杂体系的动力学行为相似.同时, 剪切带的性质尤其是其动力学行为对非晶合金的宏观力学行为和性能有重要的影响, 对理解这类材料的微观变形机理也起着重要的作用.本文结合团队近年来在非晶合金剪切带行为方面的研究结果, 对剪切带的运动行为和物理机制进行介绍, 包剪切带间歇性运动行为、以及间歇性运动在表征其动力学性质中的作用以及物理机制, 以及剪切带的自组织临界行为、物理机制等.最后对非晶合金剪切带行为研究中亟需解决的问题进行了总结和展望. 相似文献
112.
ZHANG Da-Li 《理论物理通讯》2005,43(2):295-298
Properties of the superdeformed bands of odd-odd nuclei in A~80 mass
region are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or
SU(5)) symmetry on
the rotational symmetry. The obtained γ-ray energies, and the dynamical moments of inertia agree with experimental data. It shows that this approach is quite powerful
in describing odd-odd nuclei in
A~80 mass region. 相似文献
113.
Eu3+掺杂Bi2O3-TeO2-B2O3-ZnO玻璃光谱性质 总被引:5,自引:1,他引:4
测量了Eu3+(1 mol%)掺杂(60-χ)Bi2O3-χ TeO2-30B2O3-10ZnO(χ=5,10,20,30,摩尔百分比)玻璃的吸收光谱、发射光谱、激发光谱以及声子边带谱.根据稀土离子Eu3+光学跃起矩阵元的特点,从发射光谱获得了Eu3+光学跃起的J-O参数Ω2与Ω4.结果显示,强度参量Ω2随着Bi2O3量的增加与TeO2量的减少而减小,表明材料的对称性提高, Eu-O键强减弱,共价性减弱.随着Bi2O3量的增加,电-声子偶合减弱,材料的热稳定性大幅度提高. 相似文献
114.
组态相关推转壳模型 Nilsson势研究了 C.M.Parry组最近用 EUROBALL谱仪观测到的 12 7La高自旋态结构 .实验上观测的 12 7La的宇称和辛量子数为 (π,α) =(+,- 1 /2 )的带自旋达到(83/2 ) h.理论计算结果表明该带可能具有组态 π(h11/2 ) 2 ν(h11/2 ) 6.并且几乎达到该带的带终止理论预言值 I=47.5h.该带的形变在 I≤ 40 h内处于正常形变区 (ε2 ≈ 0 .2 2 ,γ≈ 0°) ,随着角动量的增加 γ值逐渐增加 ,直到 γ=60°时带终止. HJ4/9]The configuration dependent shell correction approach with cranked Nilsson potential is employed for explaining the experimental high spin spectra in 127 La. The experimental high spin band with parity and signature (+, -1/2) consists of two parts with a crossing around I =20 . It is most like to have the configuration [02, 6], π (h 11/2 ) 2 ν (h 11/2 ) 6 and almost reaching the maximum angular momentum at I =47.5 . It is in normal deformation region with ... 相似文献
115.
Energy bands of dysprosium have been calculated considering the effects of correlation and spin-polarisation. The exchange
and correlation contributions to the spherically symmetric crystalline potential have been taken in the forms suggested by
(i) Kohn and Sham and (ii) Overhauser. The exchange and correlation potential of von Barth and Hedin has been used to study
the effect of spin-polarisation on the band structures. The resulting bandwidth, density of states, magnetic moment and spin-splitting
have been computed and compared with experimental results. Some discrepancies remain; theoretical calculations done so far
agree reasonably among themselves, so accurate experimental data are probably called for. 相似文献
116.
The ν1 region of 32SF6 and 34SF6 has been studied by stimulated Raman spectroscopy. For both isotopomers, a detailed analysis has been performed. Several hot bands (ν1+ν6−ν6, ν1+2ν6−2ν6, ν1+ν5−ν5) have been taken into account to calculate synthetic spectra that satisfactorily reproduce the experimental data. These results, together with the previous studies of the other fundamental bands have allowed us to determine the equilibrium bond length of sulfur hexafluoride as re=1.5560(1) Å, in very good agreement with recent ab initio calculations. The 2ν1−ν1 band has also been studied for both isotopomers by Raman-Raman double resonance spectroscopy and the resulting spectra have been analyzed. In this case, a striking difference is observed between the two isotopomers, since the 2ν1−ν1 band of 34SF6 appears to have a very narrow structure that could not be rotationally resolved under the present experimental conditions. All analyses have been performed thanks to the HTDS program suite (http://www.u-bourgogne.fr/LPUB/hTDS.html) dedicated to octahedral XY6 molecules. 相似文献
117.
M. Terki-Hassaïne G. Pierre V. Boudon G. Aït Hamadouche G. Guelachvili 《Journal of Molecular Spectroscopy》2005,230(2):117-124
The infrared spectrum of the SiH4 molecule has been recorded between 2040 and 2320 cm−1 using the high-resolution Fourier interferometer of the Laboratoire de Photophysique Moléculaire (Orsay, France). The resolution was 5.4 × 10−3 cm−1. In this region, many lines were previously analyzed and assigned to the ν1/ν3 stretching dyad of 28SiH4, 29SiH4, and 30SiH4 molecules [J. Mol. Spectrosc. 143 (1990) 35]. However, several lines in the spectrum were not assigned. The results obtained in our previous study [J. Mol. Spectrosc. 197 (1999) 307] of the infrared spectrum of 28SiH4, in the bending-stretching tetrad region at 3100 cm−1, enabled us to assign 204 of the observed transitions to hot bands (the ν1 + ν2/ν1 + ν4/ν2 + ν3/ν3 + ν4 bending-stretching tetrad minus the ν2/ν4 bending dyad). These transitions were used to refine the set of the Hamiltonian parameters of the bending-stretching tetrad. The analysis is performed using the tensorial formalism developed in Dijon for tetrahedral molecules and implemented in the STDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html). 相似文献
118.
G. Ugur N. Arıkan 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):319-322
The structural and electronic properties of MgAuSn in the cubic
AlLiSi structure have been studied, using density functional theory
within the local density approximation. The calculated lattice
constant for MgAuSn is found to be in good agreement with its
experimental value. Our calculated electronic structure is also
compared in detail with a recent tight-binding. A
linear-response approach to density-functional theory is used to
calculate the phonon spectrum and density of states for MgAuSn. 相似文献
119.
F. Thibault D. Cappelletti F. Pirani G. Blanquet M. Bartolomei 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(2):337-344
Integral cross sections and pressure broadening coefficients have been
measured for the acetylene — neon system by a molecular beam
scattering technique and by high infrared resolution spectroscopy,
respectively. We have performed quantal calculations using an ab-initio
potential energy surface (PES) [J. Chem. Phys. 109,
8968 (1998)]. Results are found to be in good agreement with both
measured integral cross sections and pressure broadening coefficients
for the two temperatures investigated (173 and 298 K). We have also
derived a semi-empirical PES parameterized using an atom-bond pairwise
additive scheme. This PES shows an isotropic component in agreement
with the ab-initio calculation, reproduces the scattering data but it
only leads to a reasonable agreement for the pressure broadening
coefficients. 相似文献
120.
Blauert and other researchers demonstrated that the direction of a sound image for a narrow-band noise is perceived according to the center frequency of the stimuli. Blauert referred to the frequency band by which the direction of sound image is determined as the directional band. However, it has not yet been clarified if individual differences exist in the directional bands. It is also unestablished whether the directional band changes according to the bandwidth of the stimuli. In this study, 1/3 and 1/6 octave band noises were presented from the front, above and behind the subject in the median plane, and the responses to the stimuli were analyzed individually. The results show that (1) individual differences in directional bands exist; (2) there is no remarkable difference between directional bands for 1/3 and 1/6 octave band noises; (3) for some subjects, a directional band occurs in the direction in which they could not localize wide-band noise. 相似文献