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71.
The free-vibration behavior of symmetrically laminated fiber-reinforced composite beams with different boundary conditions
is examined. The effects of shear deformation and rotary inertia, separately and/or in combination, on the free-vibration
properties of the beams are investigated. The finite-difference method is used to solve the partial differential equations
describing the free-vibration motion in each case. The effect of shear deformation on the natural frequencies is considerable,
especially for higher frequencies, whereas the influence of rotary inertia is less significant. The study includes comparisons
with results available in the literature. In addition, the impact of such factors as the span/depth ratio, fiber orientation,
stacking sequence, and material type on free vibrations of the composite beams is investigated.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 3, pp. 331–346, May–June, 2006. 相似文献
72.
73.
Sukhanova T. E. Vylegzhanina M. E. Volkov A. Ya. Gasilova E. R. Kutin A. A. Samy Moshera Abdallah Heba M. Ayoub Magdy M. H. 《Technical Physics》2019,64(12):1729-1737
Technical Physics - The morphology, structure, and optical properties of composites with biodegradable polymeric particles, which are based on poly-ε-caprolactone–polyvinyl alcohol... 相似文献
74.
Philippe Gaborit Ayoub Otmani Hervé Talé Kalachi 《Designs, Codes and Cryptography》2018,86(7):1391-1403
Encryption schemes based on the rank metric lead to small public key sizes of order of few thousands bytes which represents a very attractive feature compared to Hamming metric-based encryption schemes where public key sizes are of order of hundreds of thousands bytes even with additional structures like the cyclicity. The main tool for building public key encryption schemes in rank metric is the McEliece encryption setting used with the family of Gabidulin codes. Since the original scheme proposed in 1991 by Gabidulin, Paramonov and Tretjakov, many systems have been proposed based on different masking techniques for Gabidulin codes. Nevertheless, over the years most of these systems were attacked essentially by the use of an attack proposed by Overbeck. In 2005 Faure and Loidreau designed a rank-metric encryption scheme which was not in the McEliece setting. The scheme is very efficient, with small public keys of size a few kiloBytes and with security closely related to the linearized polynomial reconstruction problem which corresponds to the decoding problem of Gabidulin codes. The structure of the scheme differs considerably from the classical McEliece setting and until our work, the scheme had never been attacked. We show in this article that for a range of parameters, this scheme is also vulnerable to a polynomial-time attack that recovers the private key by applying Overbeck’s attack on an appropriate public code. As an example we break in a few seconds parameters with 80-bit security claim. Our work also shows that some parameters are not affected by our attack but at the cost of a lost of efficiency for the underlying schemes. 相似文献
75.
Ayoub Taavoni‐Gilan 《中国化学会会志》2019,66(6):600-607
In this study, we synthesized ofloxacin‐loaded MnFe2O4 nanoparticles (NPs) surface modified with chitosan (CS‐MnFe2O4) for prolonged antibiotic release in a controlled manner. It was found that the synthesized CS‐MnFe2O4 was spherical in shape with an average size of 30–50 nm, low aggregation, and good magnetic responsibility. An in vitro drug loading and release kinetics study reveals that the drug delivery system can take 86% of drug load and can release ofloxacin over a sustained period of 3 days. The release kinetics study reveals that the drug follows zero order kinetics and the mechanism of drug release is diffusion‐controlled type. These results indicated that CS‐MnFe2O4 NPs with pH‐sensitive properties can be used as candidates for intestinal targeted drug delivery through oral administration by avoiding the drug release in the highly acidic gastric fluid region of the stomach. 相似文献
76.
77.
Christine W. Ayoub 《Acta Mathematica Hungarica》1977,30(3-4):233-237
78.
79.
A fuzzy representation of the human operator decision-making process of selecting the maximum acceptable weight of manual lift is developed. Measures of acceptability are expressed in terms of membership functions which describe the degree to which the combined effect of biomechanical and physiological stresses is acceptable to the human operator. It is assumed that the combination of these two stresses has a synergistic effect on the individual's performance, and that the perception of this effect is reflected in an operator's choice when selecting the preferable weight of lift. The combined acceptabilities of a lifting task are compared to the subjective capacity norms established by the subjects in a psychophysical experiment. The conditions under which the distance between acceptability measures of the combined and the psychophysical stresses can be minimized are established. It is concluded that at a certain level of similarity between the acceptability measures of these stresses, a decision is made, and the preferred weight of lift selected. 相似文献
80.
P. De Padova J.-P. Ayoub J.-M. Mariot M.C. Richter A.M. Testa B. Olivieri K. Hricovini 《Surface science》2007,601(13):2628-2631
Mn0.06Ge0.94 samples have been grown by molecular-beam epitaxy on Ge(0 0 1)2 × 1. High-resolution transmission electron microscopy shows the coexistence of an ordered diluted Mn0.06Ge0.94 film and of nanoscopic crystallites, which were identified as Mn5Ge3 by electron diffraction. The magnetic properties of the Mn0.06Ge0.94 samples show a superposition of a paramagnetic behavior, due to the interaction of Mn atoms diluted in the Ge host, and a ferromagnetic behavior attributed to the Mn5Ge3 crystallites dispersed into the films. The Mn L2,3 X-ray absorption spectra of the Mn0.06Ge0.94 films exhibit a lineshape typical of metallic Mn, with considerably reduced multiplet structure. 相似文献