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991.
基于粒子群理论的板形模糊模式识别方法 总被引:3,自引:2,他引:3
带钢板形的模式识别是板形闭环控制的关键环节,板形模式的识别结果直接影响着板形控制精度.随着板形控制手段的不断更新,对板形模式识别方法提出更高的要求.为克服传统板形模式识别方法抗干扰能力差、逼近阶难以确定的缺点,依据模糊分类原理,运用欧式距离的择近原则对板形模式进行分类,完成板形信号的模式识别.在此基础上,为进一步提高识别精度,将20世纪90年代发展起来的具有全局优化能力的粒子群理论应用于板形模式识别,对模式识别的结果进行优化,并将其与单纯形法优化结果进行对比.试验结果证明了粒子群优化算法的有效性,该算法能够提高识别精度,使优化后的结果能更精确地控制板形调控机构,以适应高精度板形控制要求. 相似文献
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993.
More and more excavation projects are being performed near existing buildings and structures due to large-scale urban construction, in which the excavation unavoidably causes settlement and potential danger to the surrounding construction and buildings. For linear traffic facilities parallel to the excavation, the settlement profile parallel to the excavation, namely, the settlement along the traffic line, should also be considered. Moreover, the precise control of the differential settlement along the traffic lines also plays a very important role. Thus, it is necessary to establish a quick prediction model, which is able to consider both vertical and parallel settlement profiles, using the basic information on the excavation. Based on the large amount of field data, the characteristics of the settlement profiles are analyzed. A simplified empirical method is proposed; it is established based on the Rayleigh and Gauss distribution functions for predicting the ground settlement along railways induced by an excavation. Meanwhile, back-propagation neural networks are also used to predict the settlement behavior. A comparison between the predicted results and the monitoring data is given to verify the feasibility of the proposed method. A good agreement indicates that the proposed method can be employed to predict the settlement along railways due to an adjacent excavation. 相似文献
994.
超深地下垃圾转运站是城市地下环境物流系统的重要节点,其设计深度往往将超过50 m,由此带来了一系列复杂的岩土力学、工程力学和施工力学问题。本文阐述了转运站的概念设计和工作流程,综述了在上海地区典型软土地层进行转运站超深竖井设计施工的过程中可能会遇到的竖井周围岩土环境建模技术、竖井薄壁结构安全设计技术、竖井端部接头构造技术以及敏感环境下的竖井施工技术等关键技术问题。上述关键技术问题的分析对超深地下垃圾转运站的未来研究具有指导意义,是对现代城市大深度地下空间开发的一次有益探索。 相似文献
995.
Jianxiu Wang Bo Feng Yan Liu Lingao Wu Yanfei Zhu Xingsheng Zhang Yiqun Tang Ping Yang 《Bulletin of Engineering Geology and the Environment》2012,71(3):545-555
In China, more and more underground structures are being built close to buildings of architectural merit. When installing deep foundations, three ways of controlling seepage are suggested. In Mode III, an installed curtain extends partly into the confined aquifer so that the hydraulic connection between the excavated section and the water in the host material is partly isolated. The combined effects of pumping, curtain efficiency and recharge are discussed. Based on the engineering geological conditions of the deep foundation pit of the Yishan Road Station of Metro Line 9, Shanghai, China, in situ pumping and recharge tests were carried out. The combined effects are similar to the results obtained using a three-dimensional finite difference method (FDM) numerical simulation. 相似文献
996.
氨基甲酸乙酯(EC)是一种潜在致癌物,在黄酒发酵过程中尿素是它的前体物质。该研究通过紫外诱变和基因过表达筛选获得改良黄酒酵母菌种,并对黄酒产品的理化指标进行检测可知,与出发菌株相比,改造菌株的发酵性能和黄酒的出酒率、酒精度、总糖、总酸、氨基酸态氮和β-苯乙醇没有明显的差异,而诱变菌株JF501-A62发酵产物尿素含量降低了67%,EC含量降低了59%;基因过表达菌株JF501-B5发酵产物尿素含量降低了88%,EC含量降低了63%。两者均有很好的发酵性能,并取得了较好地降低产品中尿素含量、进而降低氨基甲酸乙酯含量的效果。与紫外诱变相比,基因过表达的改良方法获得了尿素含量更低的菌株,并贮存6个月之后产品中的EC含量更低。 相似文献
997.
998.
999.
Lihong Niu Xin Zhou Chuqiao Yuan Yun Bai Keqiang Lai Fuxin Yang Yiqun Huang 《Food Hydrocolloids》2013
Tilapia production is growing worldwide and to better utilize wastes from the processing industry, one important application is production of high quality fish gelatin to meet the needs of markets that are not amenable to beef or porcine gelatin. The extraction process from tilapia skin gelatin was optimized through the use of a combination of alkali (0.3 M NaOH) with different types and concentrations of acids before thermal hydrolysis. The effects of acid pretreatments on the protein yields and the physicochemical properties of tilapia gelatin were investigated. Acid concentrations (0.01–0.20 M) influenced gelatin protein recovery: 10.52%–22.40% for citric acid, 1.92%–21.55% for acetic acid, and 4.47%–24.35% for HCl. It was possible to increase gelatin yield for each of the tested acids by adjusting the acid concentration. Gelatin viscosity and the molecular weight distribution of gelatin proteins were related to the acid concentration used. Gelatin prepared using too low a concentration (e.g. 0.01 M acetic acid or HCl) or too high a concentration (e.g. >0.05 M HCl or citric acid) yielded an extract with a smaller ratio of large molecule components, such as β-chains, and exhibited lower viscosity. The film forming properties of gelatins extracted from three acid-optimized pretreatments showed no significant difference in transparency, tensile strength and elongation at break; though the gelatin film made from 0.03 M citric acid pretreated gelatin had somewhat better water barrier property than those made with HCl or acetic acid. 相似文献
1000.
Yiqun Li Youqing Wang Lulu Chen Xiulei Li Weihua Han 《Materials and Manufacturing Processes》2015,30(1):30-33
One-dimensional silver nanomaterials, nanorods, and nanowires (NWs) were achieved by a solution-phase method. The geometry of the silver nanostructures was successfully tuned by adding polyvinylpyrrolidone (PVP) of different molecular weights. A possible mechanism, involving the suppression effect from PVP on the growth rates at different crystal facets, is used to explain the PVP-dependent morphology of the Ag nanowires achieved in this experiment. To evaluate its potential application in transparent electrodes, we also investigated the electrical conductance and optical transmittance after NWs were transferred to transparent polyethylene terephthalate substrates. Our findings indicated a possible and simple approach to control the morphology and then the functional properties of nanostructured silvers. 相似文献