全文获取类型
收费全文 | 528篇 |
免费 | 12篇 |
国内免费 | 12篇 |
专业分类
化学 | 264篇 |
晶体学 | 14篇 |
力学 | 22篇 |
数学 | 121篇 |
物理学 | 131篇 |
出版年
2023年 | 7篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 13篇 |
2019年 | 20篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 17篇 |
2015年 | 17篇 |
2014年 | 19篇 |
2013年 | 100篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 18篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 10篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1991年 | 3篇 |
1987年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1973年 | 4篇 |
1969年 | 3篇 |
1967年 | 6篇 |
1966年 | 5篇 |
1965年 | 7篇 |
1964年 | 4篇 |
1962年 | 9篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1956年 | 3篇 |
1955年 | 4篇 |
1934年 | 2篇 |
1933年 | 4篇 |
1927年 | 2篇 |
1923年 | 2篇 |
排序方式: 共有552条查询结果,搜索用时 15 毫秒
81.
The gross structure oscillations recently observed in heavy-ion elastic or inelastic scattering and fusion cross sections are here analyzed in terms of nuclear surface (creep) wave resonances. Their dispersion curves characterize these waves as being of Rayleigh or of Whispering-Gallery type. 相似文献
82.
E. Ühlein 《Colloid and polymer science》1956,147(3):161-162
Ohne Zusammenfassung 相似文献
83.
A.S Üstünel 《Journal of Functional Analysis》1982,47(2):143-152
84.
85.
A new method to determine quasi diabatic (QD) CASSCF states is presented. The adiabatic states are subjected to a unitary transformation resulting from diagonalization of a state-selection operator. The latter is constructed from the overlap of the adiabatic states with a suitable set of reference states. The multi-state (MS) CASPT2 method is used to account for the dynamical correlation effects in an approach where the QD-CASSCF wave functions are used as reference states. The procedure is applied to avoided crossings in excited states of BeH, LiO and ozone. The advantages of the proposed formulation are discussed. 相似文献
86.
Al-Cu-Fe alloys were prepared by mechanical alloying starting from elemental powders in a high-energy planetary ball mill. Three different alloy compositions with the same c Cu : c Fe ratio of 2:1 but different aluminium contents, that is Al55Cu30Fe15, Al63Cu25Fe12 and Al70Cu20Fe10, were investigated. A sequence of solid-state reactions resulting in quasicrystalline phase formation in Al63Cu25Fe12 proceeds during milling and during annealing of the as-milled powder. These reactions were studied by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. In order to form an aluminium-matrix composite, Al63Cu25Fe12 single-phase quasicrystalline powders were blended with different amounts of aluminium. In an intermediate milling step the powder blend was homogenized. The powders were consolidated by hot extrusion. The bulk samples revealed a homogeneous dispersion of the particles in the matrix but a rather heterogeneous size distribution. The mechanical properties at room temperature were tested by constant-rate compression tests. A rule-of-mixtures dependence of the ultimate strength and the yield strength on the volume fraction of the quasicrystalline particles was found. 相似文献
87.
Non-relativistic configuration interaction (CI) ab initio calculations using large basis sets have been carried out to determine the potential curves of the first electronic states of Ne2 +, Ar2 + and Kr2 +. The spin—orbit interaction was treated assuming that the spin—orbit coupling constant is independent of the internuclear separation (R). For Ar2 +, calculated dissociation energies and equilibrium separations are in good agreement with experimental results. The calculations for Ne2 + suggest that the lowest vibrational level of the I(1/2u) ground state observed by threshold photoelectron spectroscopy by Hall et al. [1995, J. Phys. B: At. molec. opt. Phys., 28, 2435] and assigned to either ν = 0 or ν = 2 actually corresponds to ν = 4. The calculations also predict the I(1/2g) state of Ne2 + and Ar2 + to possess a double-well potential and that of Kr2 + to be repulsive at short range and to only possess a single shallow well at large internuclear separation. The ab initio calculations provide an explanation for the observation made by Yoshii et al. [2002, J. chem. Phys., 117, 1517] that Kr2 + and Xe2 + dissociate after photoemission from the II(1/2u) state to the I(1/2g) state whereas Ar2 + does not. 相似文献
88.
89.
90.
In this paper, we show the attainability of KdV equation from some types of nonlinear Schrödinger equation by using multiscale expansions discretely. The power of this manageable method is confirmed by applying it to two selected nonlinear Schrödinger evolution equations. This approach can also be applied to other nonlinear discrete evolution equations. All the computations have been made with Maple computer packet program. 相似文献