全文获取类型
收费全文 | 3600篇 |
免费 | 434篇 |
国内免费 | 355篇 |
专业分类
电工技术 | 170篇 |
技术理论 | 1篇 |
综合类 | 216篇 |
化学工业 | 28篇 |
金属工艺 | 24篇 |
机械仪表 | 225篇 |
建筑科学 | 50篇 |
矿业工程 | 77篇 |
能源动力 | 5篇 |
轻工业 | 84篇 |
水利工程 | 3篇 |
石油天然气 | 12篇 |
武器工业 | 20篇 |
无线电 | 1390篇 |
一般工业技术 | 149篇 |
冶金工业 | 17篇 |
原子能技术 | 3篇 |
自动化技术 | 1915篇 |
出版年
2024年 | 8篇 |
2023年 | 13篇 |
2022年 | 37篇 |
2021年 | 47篇 |
2020年 | 66篇 |
2019年 | 51篇 |
2018年 | 90篇 |
2017年 | 133篇 |
2016年 | 145篇 |
2015年 | 200篇 |
2014年 | 394篇 |
2013年 | 409篇 |
2012年 | 517篇 |
2011年 | 563篇 |
2010年 | 397篇 |
2009年 | 375篇 |
2008年 | 319篇 |
2007年 | 276篇 |
2006年 | 243篇 |
2005年 | 55篇 |
2004年 | 22篇 |
2003年 | 17篇 |
2002年 | 6篇 |
2001年 | 4篇 |
1999年 | 2篇 |
排序方式: 共有4389条查询结果,搜索用时 0 毫秒
61.
介绍了一种将只读射频标签和EPC-64I码应用于邮政总包处理中的方案,它可提高邮政总包的流通效率和增加邮政部门的经济效益。文章结合邮政总包生产作业特点的基础上选择了射频频率和标签类型,进行了编码和射频标签外部设计,构建了RFID应用网络系统框架,简要说明了标签的回收利用和信息注销,并对现场应用RFID的具体操作以及效果做了分析。 相似文献
62.
Marc Langheinrich 《Personal and Ubiquitous Computing》2009,13(6):413-421
A bewildering number of proposals have offered solutions to the privacy problems inherent in RFID communication. This article
tries to give an overview of the currently discussed approaches and their attributes.
相似文献
Marc LangheinrichEmail: |
63.
Robust DOA estimation and target docking for mobile robots 总被引:1,自引:1,他引:0
Direction of arrival (DOA) guided automated target acquisition and docking system is proposed for mobile robots employing
the dual-directional antenna system. The dual-directional antenna estimates the DOA of the signal of interest using the ratio
of the signal strengths between two adjacent antennas. In practice, DOA estimation poses a significant technical challenge,
since the RF signal is easily distorted by the environmental conditions. Therefore, the robot often loses its way in an electromagnetically
disturbed environment. To cope with this problem, a robust DOA estimation algorithm is developed based on Kalman filtering.
This algorithm allows the robot to reduce the potential error in the estimated DOA, and adjust the robot’s heading to the
target transponder without needing to know the positions of current and previous measurements in a global coordinate system.
The simulation and experiment results clearly demonstrate that the mobile robot equipped with the developed system is able
to dock to a target transponder in an indoor environment partially occupied by obstacles. 相似文献
64.
65.
低频唤醒技术在微功耗主动式RFID中的应用研究 总被引:1,自引:1,他引:0
微功耗主动式RFID系统的标签一般采用纽扣电池供电,其功耗是一个很关键的问题,目前常采用定时唤醒的工作方式,本文介绍了低频唤醒技术的实现原理,并讨论了将其应用到微功耗主动式RFID系统中解决射频标签内发射模块的功耗问题,给出了低频唤醒的关键电路和程序流程,实践证明该方案可以很好地解决主动式RFID的功耗问题. 相似文献
66.
The safety of patients and the quality of medical care provided to them are vital for their wellbeing. This study establishes a set of RFID (Radio Frequency Identification)-based systems of patient care based on physiological signals in the pursuit of a remote medical care system. The RFID-based positioning system allows medical staff to continuously observe the patient's health and location. The staff can thus respond to medical emergencies in time and appropriately care for the patient. When the COVID-19 pandemic broke out, the proposed system was used to provide timely information on the location and body temperature of patients who had been screened for the disease. The results of experiments and comparative analyses show that the proposed system is superior to competing systems in use. The use of remote monitoring technology makes user interface easier to provide high-quality medical services to remote areas with sparse populations, and enables better care of the elderly and patients with mobility issues. It can be found from the experiments of this research that the accuracy of the position sensor and the ability of package delivery are the best among the other related studies. The presentation of the graphical interface is also the most cordial among human-computer interaction and the operation is simple and clear. 相似文献
67.
为了解决传统RFID定位技术中存在的定位精度差和电子标签功耗高这2个问题,提出了一种基于低频触发的2.4GHz高精度区域定位系统的设计方案。该方案将低频125kHz触发信号与2.4GHz射频信号相结合,采用低频唤醒的方法极大降低了电子标签的功耗,利用可调节触发距离的触发机制将RFID系统的定位精度进一步提高.基于该方案设计了2.4GHz有源电子标签、125kHz触发器和2.4GHz阅读器三个子系统。阅读器与触发器的分离式设计,节约了铺设成本。系统硬件电路设计中加入了可调电位器和数字电压调节器,分别对识别距离和触发距离进行调节,使设备的配置更为方便,增强了系统的实用性。测试数据显示,阅读器与标签的最大通信距离长达120m,有源电子标签的待机时间约为2a(年),RFID定位系统能够实现1~5.2m的可调定位精度。测试结果验证了该方案的有效性。 相似文献
68.
Recent research has demonstrated the potential benefits of radio frequency identification (RFID) technology in the supply chain and production management via its item-level visibility. However, the RFID coverage performance is largely impacted by the surrounding environment and potential collisions between the RFID devices. Thus, through RFID network planning (RNP) to achieve the desired coverage within the budget becomes a key factor for success. In this study, we establish a novel and generic multi-objective RNP model by simultaneously optimising two conflicted objectives with satisfying the heterogeneous coverage requirements. Then, we design an improved multi-objective genetic algorithm (IMOGA) integrating a divide-and-conquer greedy heuristic algorithm to solve the model. We further construct a number of computational cases abstracted from an automobile mixed-model assembly line to illustrate how the proposed model and algorithm are applied in a real RNP application. The results show that the proposed IMOGA achieves highly competitive solutions compared with Pareto optimal solutions and the solutions given by four recently developed well-known multi-objective evolutionary and swarm-based optimisers (SPEA2, NSGA-II, MOPSO and MOPS2O) in terms of solution quality and computational robustness. 相似文献
69.
介绍了井下三维人员定位系统的组成、工作原理、功能及关键技术。该系统采用射频识别技术、ZigBee技术及3D技术,可实时识别与跟踪井下人员动态,并通过计算机网络采集、传送数据;还可通过仿真矿井虚拟现实井下人员的考勤、分布状态及运动轨迹,可在事故发生后为矿井人员的抢救提供可靠的位置信息,提高抢险救灾的效率。 相似文献
70.
李敬红 《计算机与数字工程》2011,39(12):104-107
针对涉密文件特别是纸介质文件管理上存在的安全问题,基于RFID技术设计实现了涉密文件管理系统。该系统采用了文件监控与安全报警的方法,实现涉密文件高效安全的管理,降低了泄密事件的发生率,实现了利用自动化设备对纸介质涉密文件进行监控管理的设想。 相似文献