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排序方式: 共有123条查询结果,搜索用时 62 毫秒
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Neural Computing and Applications - In recent years, researchers have proposed many methods to solve the problem of obstacle detection. However, computer vision-based vehicle detection and... 相似文献
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Neural Computing and Applications - Image classification method is currently the more popular image technology, but it still has certain problems in practice. In order to improve the image... 相似文献
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The crystal size distribution (CSD) measured by laser diffraction technique is obtained by assuming spherical crystals. If crystals are non-spheres, calibration is responsible for the true crystal size, particle number concentration and population density. In this paper, CSD calibration equations have been deduced. It was shown that when shape factors are size-independent, the weight percent of particles is not affected by crystal shape and calibration is just a horizontal shift of measured CSD. Calibration was taken for plate-like crystals of cefazolin sodium and rod-like crystals of l-threonine. The effect of CSD calibration on crystal growth kinetics has been investigated in l-threonine-water evaporation crystallization system. 相似文献
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介绍当前智能家居设备互联架构及方式,论述现有智能家居设备中电力线通信加密方法存在的问题.提出一种基于NFC的电力线通信加密方法,该方法使用NFC卡的UID生成网络密钥并对电力线网络链路进行加密.实测表明,该方法较好的解决了现有电力线通信加密存在的问题,增加了NFC读卡的便捷性、准确性、稳定性,具有较高的安全性,对外界干扰具有较强的抑制能力. 相似文献
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Dynamic disturbance is sometimes a non-ignorable factor to induce rock failure in underground excavation, especially for high initial geo-stressed locations. In this study, a mathematical physics model was used to characterize the failure mode of brittle rock under static geo-stress and dynamic loading. An implicit to explicit sequential solution method (IESSM) was performed to examine the dynamic fracturing behavior of an underground opening due to dynamic disturbance. In the numerical simulation, the characteristics of strain energy density (SED) and fracturing zone were investigated under various lateral pressure coefficients. The results indicated that different failures were induced around the opening subjected to dynamic. With lower lateral pressure coefficient, spalling is induced at roof and spandrel with a long period for releasing strain energy. With the increase of the lateral pressure coefficient, violent strain rockbursting is observed in highly stressed locations, with instantaneous release of massive strain energy. Moreover, when the geo-stress of lateral pressure coefficient is high enough, the occurrence location and fracturing zone of rockbursting will not be greatly influenced by the dynamic disturbance, including its amplitude and action direction. 相似文献
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In this paper we investigate predictability of electricity prices in the Canadian provinces of Alberta and Ontario, as well as in the US Mid-C market. Using scale-dependent detrended fluctuation analysis, spectral analysis, and the probability distribution analysis we show that the studied markets exhibit strongly anti-persistent properties suggesting that their dynamics can be predicted based on historic price records across the range of time scales from 1 h to one month. For both Canadian markets, the price movements reveal three types of correlated behavior which can be used for forecasting. The discovered scenarios remain the same on different time scales up to one month as well as for on- and off-peak electricity data. These scenarios represent sharp increases of prices and are not present in the Mid-C market due to its lower volatility. We argue that extreme price movements in this market should follow the same tendency as the more volatile Canadian markets. The estimated values of the Pareto indices suggest that the prediction of these events can be statistically stable. The results obtained provide new relevant information for managing financial risks associated with the dynamics of electricity derivatives over time frame exceeding one day. 相似文献
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Wireless Networks - This paper studied the issue of communication transmission power cost optimization for the personal body base station in wireless body area network (WBAN). With the limited... 相似文献
10.
气井稳定携液之我见 总被引:1,自引:0,他引:1
业内对于临界携液流量的认识一直都存在着分歧。以Turner、李闽为代表的液滴携液理论观点认为"当气体流速达到一定数值后,液相分散成小液滴被携带走";而以李颖川等为代表的气液两相管流实验模拟者则认为"在气井生产过程中雾状流很难出现,气井生产基本上是以段塞流为主,液滴模型无法解释气井实际排液情况"。为了还原低压低产气井实际生产状态,基于弗劳德相似准数,以流速相似原理模拟低压、低产井实际生产情况,并开展了相应的实验研究。结果表明:①低压、低产气井实际上存在"上雾+下段塞"混合流动状态;②上部雾状流携液满足液滴模型计算结果,当气相流速高于临界携液流速则上部可连续带液,否则会导致积液段液量缓慢增加;③下部表现为段塞流,当气相流速高于1.95 m/s,则表现为连续流动,气井基本无积液,当气相流速低于0.195 m/s,则表现为难以流动,气井不产液,面临水淹。实验所得结果与气井实际生产情况相当吻合,可以为气井有效开采提供技术支撑。 相似文献