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61.
AbstractAs new environmentally friendly techniques, hydride materials have been proposed to be introduced to fast reactor (FR) cores in this paper. Hydrogen atoms in metal hydride can efficiently moderate fast neutrons. Based on this fact, some metal hydrides have been investigated for their potential environmentally friendly application as nuclear materials to be used in FR cores. Two types of utilisation of metal hydrides in FR cores are discussed in this paper. One is the application of hafnium hydride as neutron absorber in FR cores. The core design has been carried out to examine its characteristics as well as to evaluate the cost reduction effect. Demonstration of the fabrication of hydride pins has been performed using hydride pellets and stainless steel claddings. The coating technique of the inner cladding surface has also been developed to reduce the permeation of hydrogen through the stainless steel cladding. The physical and chemical properties of the pellet have been measured for the purpose of designing a hafnium hydride pin. Irradiation test of the hydride pins has been performed in the experimental FR, JOYO, Japan Atomic Energy Agency. The other application is the utilisation as a transmutation target of long lived nuclear wastes. Hydride fuel containing 237Np, 241Am and 243Am has been studied for a candidate transmutation target to be used to reduce the radioactivity of long lived nuclides contained in the nuclear wastes, which are obtained after reprocessing spent fuels. 相似文献
62.
LIU KaiHuang LIU TianCheng LI JianLiang ZHANG Liang ZHANG HongHao LI DeRen LU ZhiChao & ZHOU ShaoXiong China Iron Steel Research Institute Beijing China Advanced Technology Materials Co. Ltd. 《中国科学:信息科学(英文版)》2010,(4)
A composite consisting of flake-shaped Fe74Cr2Mo2Sn2P10Si4B4C2 particles was prepared.The flake-shaped particles included in the composite were prepared by planetary ball milling.The complex permeability of the composite material was measured at frequency range from 10 MHz to 8.5 GHz.The permeability of the composite containing flake-shaped particles was much higher than that of the spherical particles.The permeability of particles was improved by means of heat-treatment.In contrast to the random-spatial-di... 相似文献
63.
Sophisticated portable infrared imagers developed for surveillance, reconnaissance, targeting and navigation play a vital role in the modern tactics used for carrying out military and antiterrorist operations. Their superior performance relies on novel optronic technologies and maintaining the infrared focal plane arrays at cryogenic temperatures using close cycle mechanical Stirling cryogenic coolers.Such coolers are well known sources of high-frequency interference contaminating the image signal and causing essential degradation in the overall imagery performance. This phenomenon is generally referred to as microphonics, which mostly manifests itself at the resonant frequencies of sensitive mechanical components of infrared packages.The ruggedizing of these components involves stiffening and dampening which are, evidently, not the best solutions to implement inside, say, an evacuated envelope, where the issues of added heat load, thermal mass, ageing, vacuum contamination due to outgassing are of the primary concern.The paper examines the idea of using externally mounted wideband dynamic absorbers for suppressing the above resonant responses and associated microphonic noise. The suggested analytical model relies on a set of complex frequency response functions experimentally captured on the original infrared package. The optimised dynamic absorber yields about a tenfold suppression of the resonant responses and a threefold attenuation of the overall RMS level of microphonic noise. The results of the analytical prediction are in fair agreement with experimental data. 相似文献
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A nonlinear mathematical model for the shock absorber in TJ7100 is developed. The oil compressibility and the entrapped gas in the oil are considered in the model. As a result, the hysteresis in the force-velocity diagram is included. The results of computer simulation and the experiment are basically identical. The MATLAB/SIMULINK is used for the development of the simulation software. It is found that the pressure inside the cylinder is high if the inputs of velocity or displacement are big by simulation. This is certainly one of the main reasons for which the leak is appeared between the rod and the seal of the shock absorbers for a relatively short time in China. 相似文献
68.
《Thin》2013
Adding complex sinusoidal patterns on wall surfaces has been recently suggested in literature as an effective innovation for improving energy dissipation of thin walled box beams during axial collapses. This paper studies the energy absorption efficiency and performance of patterned beams under pure bending. A numerical investigation is carried out using commercially available Marc Mentat™ solver and the investigation is also verified using existing analytical models. Five different types of patterns are tested. The result of adding patterns on individual and combination of walls and the effect of progressive triggering proposed previously in literature on the maximum bending moment of the beam is also studied. Results indicate that the beams with sinusoidal patterns are significantly better in energy absorption in deep bending collapse; an increase of about 53.49% at 0.6 rad is noted in the optimal case. The pattern types which had higher energy absorption in axial impact reflect the same trend in bending collapses. This research may further endorse the viability of using sinusoidal patterned beams in mainstream practical applications. 相似文献
69.
E. Sani L. Mercatelli S. Barison C. Pagura F. Agresti L. Colla P. Sansoni 《Solar Energy Materials & Solar Cells》2011,95(11):2994-3000
The optical characterization is reported of a new fluid consisting of single-wall carbon nanohorns and ethylene glycol for solar energy applications. Carbon nanohorns play a significant role in enhancing sunlight absorption with respect to the pure base fluid. The obtained results are compared with those obtained for fluids suspending more conventional carbon forms, i.e. carbon-black particles. We found that nanohorn spectral features are far more favorable than those of amorphous carbon for the specific application. This result shows that carbon nanohorn-based nanofluids can be useful for increasing the efficiency and compactness of thermal solar devices, reducing both environmental impact and costs. 相似文献
70.
《分离科学与技术》2012,47(15):2445-2466
Abstract In this paper an extended analysis on a hollow-fiber membrane absorber is conducted for CO2 removal from flue gases. A rigorous model of gas–liquid mass transfer is developed on both narrow channels in and around the hollow fibers, including the gas absorption occurring from the reaction between CO2 and aqueous K2CO3 absorbent. CO2 concentration profiles can be obtained regardless of the placement of the flowing absorbent. Experimental observations of the CO2 concentration in both the reject and permeate outlets compared with theoretical prediction allow us to understand the influence of flow rates of feed gas as well as absorbent on CO2 absorption. For the flowing K2CO3 absorbent a kinetic constant can be chosen which will provide the best possible agreement between experiment and reactive model prediction. This fact emphasizes that the pseudofirst-order kinetic can be employed to describe the facilitation effect. The overall mass transfer coefficients were determined from the experimentally observed concentration changes. The CO2 permeation flux was found to be enhanced as the K2CO3 concentration was increased, suggesting that CO2 removal is entirely controlled by the reaction. The enhanced selectivity factor for CO2/N2, which decreases with increasing absorbent flow rate, reached as high as 1200 with 15 wt% K2CO3 absorbent. 相似文献