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91.
Polypropylene (PP)/polyamide6 (PA6)/ethylene propylene diene monomer (EPDM) (70/15/15) ternary polymer blends compatibilized with maleic‐anhydride‐grafted EPDM (EPDM‐g‐MA) were prepared by melt blending using a twin‐screw extruder (TSE) in different processing conditions (barrel temperature profile, screw speed, and mixing sequence). The microstructures of prepared ternary blends were studied and compared to the predictions of spreading coefficient, minimum relative interfacial energy (RIE), and dynamic interfacial energy phenomenological models. The observed morphologies were somehow different from the model predictions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
92.
D. Naderi B. Miripour Fard M. Sadeghi-Mehr 《Communications in Nonlinear Science & Numerical Simulation》2013,18(1):99-108
Previous studies have suggested that human beings movements can be related to the problem of cost function minimization. But at the present time it is not clear that which objective function(s) and constraints are used by central nervous system (CNS) to produce optimal reactions under perturbations. Present study has been done experimentally and by numerical simulations to explore the stability constraints which should be used in combination with energy based cost function (weighted minimum torque) to estimate the motor planning criterion is used by CNS for disturbance rejections. The influence of three stability criterions (ZMP, extrapolated center of mass and a vertical force criterion) in combination with minimum torque model on the optimal trajectory formation is investigated. First, the response of 10 male healthy persons to platform oscillation was recorded by motion analysis system and the hip, knee and ankle angular trajectories were derived from recorded data. Second, the dynamic simulation of a four-segment, three actuated degrees of freedom mechanical model of the human body was performed using predictive dynamic method which leads to an optimization problem. The simulated trajectories were then compared to the experimental data. With comparison between experimental results, the weighting coefficients of the objective function were found to achieve best estimation. It was seen that the minimum torque objective function with weighting coefficients gives trajectories that are mostly matched with experimental observation. Moreover, the results showed that between stability criterions, the ZMP predictions are near to experimental results. Although by using vertical force criterion some nearness to experimental results are lost (in comparison with ZMP criterion) but a secured flat-foot posture for the model is obtained which this posture is more applicable than others in humanoid implementations. 相似文献
93.
The neutron detector with 3He -filled counters placed in the focal plane of the VASSILISSA separator is used for measuring the average number and determining the multiplicity distribution of prompt neutrons from the spontaneous fission of heavy short-lived isotopes. The test reaction $\ensuremath \mathrm{{}^{48}Ca}+\mathrm{{}^{206}Pb}=2{\rm n}+\mathrm{{}^{252}No}$ is used for tuning the separator settings and calibrating the detector system with the spontaneous fission of the 252No . The average neutron number per 252No spontaneous fission event is as large as $\ensuremath \bar{\nu}=4.06 \pm 0.12$ . The short-lived heavy isotope 244Fm , produced in the complete fusion reaction 40Ar + 206Pb , is investigated. The average number of neutrons per spontaneous fission of 244Fm from the experimental data ( $\ensuremath \bar{\nu}=3.3 \pm 0.3$ is determined for the first time. 相似文献
94.
95.
Employing density functional calculations including an empirical dispersion term, we investigated the hydrogenation of an aluminum nitride nanosheet (h-AlN) with atomic and molecular hydrogen. It was found that atomic H prefers to be adsorbed on an N atom rather than Al, releasing energy of 21.1 kcal/mol. The HOMO/LUMO energy gap of the sheet is dramatically reduced from 107.9 to 44.5 kcal/mol, upon the adsorption of one hydrogen atom. The adsorption of atomic H on the h-AlN presents properties which are promising for nanoelectronic applications. The molecular H2 was found to be adsorbed collinearly on an N atom and dissociated to two H atoms on Al–N bond. Calculated barrier and adsorption energies for this dissociation process are about +18.9 and ?1.9 kcal/mol. We predict that each nitrogen atom in an AlN sheet can adsorb two hydrogen molecules on opposite sides of the sheet, and thus the gravimetric density for hydrogen storage on AlN sheet is evaluated to be about 8.9 wt%. 相似文献
96.
Chitosan-N-poly(ethylene glycol) brush copolymers with different degree of substitution (DS) were synthesized via reductive amination of chitosan by methoxy poly(ethylene glycol) (MPEG) aldehyde. Chitosan-N-MPEG copolymers were high-molecular-weight products with desirable DS; solubility and solution viscosity of those copolymers depended on the method of the synthesis of MPEG aldehyde and on DS. Synthesis of MPEG aldehyde by the use of TEMPO radical/BAIB was not suitable because of partial oxidation of methoxy groups of MPEG resulting in bifunctional PEG derivatives leading to cross-linking. Adsorption studies of chitosan-N-MPEG graft copolymers on silica surface show that these polymers adsorb in highly hydrated layers. 相似文献
97.
We investigate the equation of state of kaon condensed neutron star matter using the lowest order constrained variational (LOCV) method. In this paper, we employ the AV18 and AV14 potentials for nucleon-nucleon interaction and use the chiral model for kaon-nucleon interaction. According to our results, the kaon condensation occurs at some density values and softens the equation of state as other techniques have shown. 相似文献
98.
99.
Hamidreza Tavakoli Jelena Mii Majid Naderi Vojislav B. Mii 《Wireless Communications and Mobile Computing》2016,16(4):393-407
We present, model, and evaluate a novel clustering algorithm running on top of IEEE 802.15.4 wireless sensor networks operating in slotted, beacon‐enabled mode. The adaptive low‐energy clustering algorithm provides randomized sleep and randomized rotation of the cluster‐head role so as to maximize the useful lifetime of the network by improving efficiency and balancing the lifetime of individual nodes. We model the adaptive low‐energy clustering algorithm through probabilistic analysis and show that its parameters can be tuned to extend the network lifetime and reduce the delay and energy overhead imposed by clustering. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
100.
Naderi Mohammad Javad Buchanan Austin Walteros Jose L. 《Mathematical Programming》2022,195(1-2):517-551
Mathematical Programming - The usual integer programming formulation for the maximum clique problem has several undesirable properties, including a weak LP relaxation, a quadratic number of... 相似文献