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1.
《矿业科学技术学报(英文版)》2020,30(3):405-411
Poor road conditions in underground mine tunnels can lead to decreased production efficiency and increased wear on production vehicles. A prototype system for road condition monitoring is presented in this paper to counteract this. The system consists of three components i.e. localization, road monitoring, and scheduling. The localization of vehicles is performed using a Rao-Blackwellized extended particle filter, combining vehicle mounted sensors with signal strengths of Wi Fi access points. Two methods for road monitoring are described: a Kalman filter used together with a model of the vehicle suspension system, and a relative condition measure based on the power spectral density. Lastly, a method for taking automatic action on an ill-conditioned road segment is proposed in the form of a rescheduling algorithm.The scheduling algorithm is based on the large neighborhood search and is used to integrate road service activities in the short-term production schedule while minimizing introduced production disturbances.The system is demonstrated on experimental data collected in a Swedish underground mine. 相似文献
2.
After the “imported” urban forms, which originated from foreign cultures, were transplanted into Chinese cities, they generate brand-new urbanscape but suffer from a lack of cultural roots and a disconnection with the mainstream of contemporary urban planning. Thus, their current value and potential in urban renewal are questioned. The study takes the circular–radial space from the Baroque cities as an example to clarify the motivation of its import from the west to northeast China. It further clarifies their adaptive changes in form and function in the local urban context, through a case study on Dalian City. The study finds that different geometric patterns of existing circular–radial space were influenced by European, American, and Japanese urban planning theories to varying degrees, but with equal emphasis on symbolism and functionality. Their implementation in Dalian has a continuity in time and space. But due to the changes in topography, traffic, and planning concepts, their forms and functions tend to be independent, their connection weakens, and their importance recedes after the street network. The circular–radial space in Dalian led to distinctive urbanscape. But during their inheritance and transformation, the rationality of new forms and functions, as well as the necessity of continuing the initial ones need to be dialectically considered, so as to avoid dogmatic revival and antique reproduction. Finally, the study reconsiders the concept of “localization” of “imported” urban form, and constructs a general research pattern to provide a new perspective for understanding the transformation of similar types of urban forms. 相似文献
3.
目的:观察B超定位行ESWL对输尿管中段结石的治疗效果及分析其技术特点。方法:对176例输尿管中段结石采用ESWL治疗进行回顾性分析。结果:176例输尿管中段结石,治愈率达到95.5%。结论:B超定位行ESWL是治疗输尿管中段结石最简便、最快捷、痛苦最少的一种有效治疗方法。 相似文献
4.
Many applications of Swarm Robotic Systems (SRSs) require each robot to be able to discover its own position. To provide such capability, some localization methods have been proposed, in which the positions of the robots are estimated based on a set of reference nodes in the swarm. In this paper, a distributed and resilient localization algorithm is proposed based on the BSA–MMA algorithm, which uses the Backtracking Search Algorithm (BSA) and the Min–Max Area (MMA) confidence factor. It is designed in a novel four-stage approach, where a new method, called Multi-hop Collaborative Min–Max Localization (MCMM), is included to improve the resilience in case of failures during the recognition of the reference nodes. The results, obtained with real Kilobot robots, show 28–36% of performance improvement obtained by the MCMM. Also, it is shown that the final result of the localization process is better when the MCMM is executed than if it is not executed. The experiments outcomes demonstrate that the novel four-stage approach and the use of the MCMM algorithm represents a progress in the design of distributed localization algorithms for SRS, especially with regard to its resilience. 相似文献
5.
当前基于迭代最近点拼接的同时定位与建图算法,存在误差积累、无法满足大范围定位精度的缺陷。为此,提出一种融合多帧迭代最近点和图优化的算法。在时域上处理点云拼接问题,将单帧迭代最近点算法推广到多帧进行最近点迭代,提取同一地点在不同时刻的数据特征,形成多个封闭循环,再运用基于最小二乘的图优化方法对点云拼接后的全网数据进行全局优化,消除累计误差,提升整体的定位精度。采用鲁巷和密歇根的数据进行测试,结果表明,该方法在一定程度上减少了匹配误差,平均误差为1.0m,最小误差为0.2m,可以满足大范围同步定位与建图的精度需求。 相似文献
6.
Nikolay Tcholtchev Ina Schieferdecker 《International Journal of Communication Systems》2014,27(12):4103-4125
A main requirement for the Future Internet is to enable self‐management behaviors facilitating the network to adapt to changing conditions and self‐heal in the face of erroneous states. On the basis of Autonomic Fault‐Management principles, this paper proposes a framework consisting of a set of components operating inside the network elements and allowing the devices to collaboratively realize self‐healing. In that context, Autonomic Fault‐Management is intuitively constituted by the detection of the presence of faulty conditions, followed in turn by the self‐diagnosis and identification of the corresponding root causes, and completed consequently by the removal of the identified root causes and their effects. The proposed framework implements a distributed control loop that interacts with the network operations personnel in case the current erroneous state is not resolvable by means of Autonomic Fault‐Management. We argue that there are a number of mutual benefits between our proposed framework and the IPv6 protocol suite. This is demonstrated by a case study that illustrates these benefits and shows how the capabilities of IPv6 can be enhanced through the self‐healing mechanisms of the proposed framework. Finally, the prototype implementation used for the case study is analyzed in terms of scalability and overhead produced in the network nodes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
7.
Node localization is important in WSNs (Wireless sensor networks) applications. We present a new cruise positioning algorithm, where a single beacon node cruises an entire network, broadcasting its position periodically with fixed signal strength. Meawhile, an unknown node obtains the location and the corresponding distance of the beacon node. Two possible position coordinate sets for the unknown node can then be calculated, and the coordinate mean of the point set with a small variance is an unbiased estimator of the unknown node's coordinate. The positioning algorithm's computation is simple, positioning accuracy is not limited by a physical distance measuring tool, and there are no restrictions on the path of motion, which makes it more realistic. An algorithm simulation is presented to compare the original and cruise location algorithm. Numerical results show that the cruise localization algorithm can achieve good positioning accuracy. 相似文献
8.
《Mechatronics》2015
While omnidirectional wheels enable a holonomic drive and a good maneuverability, the slippage of the wheels as an inherent characteristic of the omnidirectional wheels prevents using rotary shaft encoders as a reliable source of data for the robot’s odometry. When installed on a climbing robot, omnidirectional wheels may suffer from additional slippage on the surface. In a previous study, we described how the resulting vibration decreases the trajectory following accuracy of the robot, and why rotary encoders, as the most popular dead reckoning method cannot be used. In this paper, we address this problem by integration of low cost and light weight exteroceptive sensors, i.e. an accelerometer and an optical flow sensor. The Omniclimber climbing robot was used as the testing platform in this study. Omniclimbers are omnidirectional climbing robots that can climb and navigate over flat and curved structures. We attempt to compensate the errors due to the wheel slippage through closing the position control loop without significantly increasing the robot’s weight, cost and complexity of the robot. We also integrated an algorithm which corrects the robot kinematics on the curved structures based on the curvature diameter and the robot’s heading angle. Taking advantage of these sensors and algorithms we could make remarkable improvements on the path following accuracy of the Omniclimbers, which is presented in this article. 相似文献
9.
《Measurement》2016
Evaluation of the tolerance zone using discrete measured points plays a critical role in today’s manufacturing, metrology, and many industrial applications. The deviation zone is typically evaluated using a fitting method that locates an ideal desired geometry corresponding to a set of measured points while a function of the Euclidean distances of the measured points to the ideal surface becomes minimum. This paper presents a quick and reliable algorithm called Dynamic Principle Component Alignment (DPCA) for fitting complex surfaces to the coordinate metrology measured points using the information that is dynamically generated by Principal Component Analysis (PCA) of the measurement data and the corresponding fitted geometry. The developed algorithm efficiently eliminates the necessity for applying commonly used optimization methods for the fitting (localization) process, which decreases the computational cost and uncertainty of the evaluation process. Moreover, DPCA is very reliable and practical in coordinate metrology with large data sets in processes such as laser scanning and other optical methods. The results show that the proposed methodology more accurately finds fitting parameters in comparison with the other commonly used methods while the computational cost is considerably reduced. 相似文献
10.
近年,我国木结构建筑得到了良好的发展,市场前景广阔。如何实现现代木结构建筑产业的国产化、本土化成为今后发展急需解决的关键问题之一。本文从现代木结构建筑的原材料、生产技术及建筑风格等方面探讨了实现木结构建筑国产化的途径。 相似文献