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301.
302.
In this paper a thick short length hollow cylinder made of functionally graded materials (FGMs) under internal impact loading is considered. The inner surface of the cylinder is pure ceramic, the outer surface is pure metal, and the material composition varies continuously along its thickness. Finite Element Method based on Rayleigh-Ritz energy formulation has been applied to study the propagation of elastic waves in FG thick hollow cylinders. The Newmark direct integration method is applied to solve the time dependent equations. The time histories of displacements, stresses, wave propagation in two directions and velocities of radial stress wave propagation for various values of volume fraction exponent have been investigated. Also by using fast Fourier transform, the first natural frequencies for FG cylinders with simply-simply and clamped-clamped ends conditions are illustrated. The model has been compared with result of a plane strain FG thick hollow cylinder which is subjected to an internal impact loading, and it shows very good agreement. 相似文献
303.
In this paper a thick hollow cylinder with finite length made of two dimensional functionally graded material (2D-FGM) subjected
to transient thermal boundary conditions is considered. The volume fraction distribution of materials, geometry and thermal
boundary conditions are assumed to be axisymmetric but not uniform along the axial direction. The finite element method with
graded material properties within each element is used to model the structure and the Crank–Nicolson finite difference method
is implemented to solve time dependent equations of the heat transfer problem. Two-dimensional heat conduction in the cylinder
is considered and variation of temperature with time as well as temperature distribution through the cylinder are investigated.
Effects of variation of material distribution in two radial and axial directions on the temperature distribution and time
response are studied. The achieved results show that using two-dimensional FGM leads to a more flexible design so that transient
temperature, maximum amplitude and uniformity of temperature distributions can be modified to achieve required specifications
by selecting a suitable material distribution profile in two directions. 相似文献
304.
We demonstrate a compact and slitless spectrometer with high resolution formed by cascading a Fabry-Perot etalon (FPE) and a cylindrical beam volume hologram (CBVH). The most significant advantage of this combined spectrometer is that we can independently encode spectral information of a diffuse beam in a 2D plane. Also, we show that in this slitless configuration we can simultaneously benefit from the advantages of both elements: the high resolution of the FPE and the large spectral range of the CBVH. Here, we report on the experimental demonstration of a spectrometer with better than 0.2 nm resolution. 相似文献
305.
In this paper transient thermal stresses in a thick hollow cylinder with finite length made of two-dimensional functionally
graded material (2D-FGM) based on classical theory of thermoelasticity are considered. The volume fraction distribution of
materials, geometry and thermal load are assumed to be axisymmetric but not uniform along the axial direction. The finite
element method with graded material properties within each element is used to model the structure. Temperature, displacements
and stress distributions through the cylinder at different times are investigated. Also the effects of variation of material
distribution in two radial and axial directions on the thermal stress distribution and time responses are studied. The achieved
results show that using 2D-FGM leads to a more flexible design so that time responses of structure, maximum amplitude of stresses
and uniformity of stress distributions can be modified to a required manner by selecting suitable material distribution profiles
in two directions. 相似文献
306.
Rabbani Yahya Hajinajaf Nima Tavakoli Omid 《Journal of Thermal Analysis and Calorimetry》2019,135(3):1687-1697
Journal of Thermal Analysis and Calorimetry - In this study, silicone oil as the base fluid and carbonyl iron powder with the average particle size of 2.7 µm as the disperse phase was... 相似文献
307.
308.
In disordered spin systems with antiferromagnetic Heisenberg exchange, transitions into and out of a magnetic-field-induced ordered phase pass through unique regimes. Using quantum Monte Carlo simulations to study the zero-temperature behavior, these intermediate regions are determined to be Bose-glass phases. The localization of field-induced triplons causes a finite compressibility and, hence, glassiness in the disordered phase. 相似文献
309.
An experimental study of variation of sensitivity with recording and sensitizing intensities in two-center recording is presented. The experimental results are in good agreement with the theoretical predictions. It is shown experimentally, for what is to our knowledge the first time, that the sensitivity is a function of the ratio of recording to sensitizing intensities and not the absolute intensities. Also, the ratio of recording to sensitizing intensities should be small to obtain high sensitivity values. We also report the highest sensitivity (S=0.15 cm/J) that has been achieved to date for a LiNbO3:Fe:Mn crystal. 相似文献
310.
[structure: see text] The widely used internal standard for NMR studies in aqueous solution DSS (sodium 4,4-dimethyl-4-silapentane-1-sulfonate) can interact with cationic peptides, diminishing its value for such studies. This paper introduces DSA (4,4-dimethyl-4-silapentane-1-ammonium trifluoroacetate) as a new internal standard that does not suffer from this problem. 相似文献