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In this paper, we present a novel narrow-frame antenna with a size of 75 × 8 × 5.8 mm3 for 5.7 in. mobile phones. The antenna mainly consists of a monopole with four branches that are coupled to a two-branch grounded strip. Our antenna is able to cover more bands than other narrow-frame antennas by excitation of several resonant modes. The improved range of the antenna covers the following eleven bands: LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, LTE3400 (3400–3800 MHz)/WiMAX3.5 GHz (3400–3650 MHz), WLAN5.2 GHz (5150–5350 MHz) and WLAN5.8 GHz (5725–5875 MHz). Another advantage of the proposed antenna is that it does not need any lumped element to match the antenna. The working principles of the proposed antenna are thoroughly studied. A prototype of the proposed antenna is fabricated and measured, with the results in good agreement with the simulation results. 相似文献
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Natalia Vassileva Yevgeni Koucheryavy 《Wireless Communications and Mobile Computing》2015,15(4):666-684
The adaptive modulation and coding (AMC) technique, which has been adopted by advanced mobile telecommunication systems, supports a flexible response to the random radio behaviour. As a result, the attained transmission rate over a wireless link is time varying. Hence, resource demands are not deterministic but fluctuating even for calls with constant bit rate service requirements. Consequently, constant bit rate calls are susceptible to a forced call termination because of insufficient resources not only in a target cell during inter‐cell handoffs but also in a serving cell during radio link deterioration. Furthermore, call blocking and dropping probabilities depend on radio propagation conditions among other factors and therefore they are dissimilar throughout a service area. The latter leads to unfairness problems. We analytically measure the impact of AMC on fixed‐rate service with hard delay constraints such as voice for different signal, mobility and traffic conditions. We consider a reference case (call requests are admitted into the system provided there are enough free resources) and two classes of admission control approaches: traditional (only inter‐cell handoffs are prioritised) and modified (all ongoing calls are prioritised). The reported results reveal conditions for which AMC affects voice call performance and can serve as guidelines on admission control design. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Fahimeh Rezaei Michael Hempel Hamid Sharif 《Wireless Communications and Mobile Computing》2015,15(8):1290-1307
Advances in wireless communication protocols and networking toward support of the next generation of mobile and radio broadband technologies have contributed to a strong competition among various telecommunication standards in particular Long Term Evolution (LTE) and Mobile Worldwide Interoperability for Microwave Access (WiMAX). In this paper, we provide an in‐depth comparison analysis of LTE and Mobile WiMAX at the physical (PHY) layer by studying the most similar PHY configuration scenarios for these two technologies. Our study includes a throughput analysis of downlink (DL) and uplink (UL) transmissions in time division duplex with the least overhead possible and different antenna schemes as well as modulation and code rates. This study also performs an overhead analysis in both protocols to provide a more in‐depth understanding of the PHY layer capacity in various PHY layer configurations. Our simulation results generally show higher performance for LTE in both DL and UL transmission with 7 Mbps in DL and 5 Mbps in UL, when using one antenna port. However, by increasing the number of antennas for multiple‐input/multiple‐output configurations, the results illustrate a reduction in the performance of LTE compared to Mobile WiMAX. This arises from the increase in reference signal overhead in LTE from 4.7% in single‐input/single‐output (SISO) to 14.28% in 4 × 4 multiple‐input/multiple‐output (MIMO). Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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本文首先介绍了WiMAX的技术特点,然后着重对WiMAX技术的当前两大主流业务--中小企业数据和语音业务、家庭用户数据和语音业务进行了经济分析,提出在当前情况下,WiMAX可以考虑在有一定业务需求的地方进行部署,最后对WiMAX的应用进行了分析和探讨. 相似文献
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移动WiMAX的频率复用分析 总被引:1,自引:0,他引:1
本文首先简述了网络规划和频率复用问题,然后重点介绍了移动WiMAX在频率复用系数分别为1和3时的对比及分析,得出系统单扇区复用系数为3时的效率要优于复用系数1,但是基站的整体效率则是复用系数为1占优,而这时又会产生较大的干扰,采用部分频率复用则可很好地解决这个问题,最大化了整体频谱效率. 相似文献
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陈韵钊 《电信工程技术与标准化》2007,20(7):76-80
本文根据WiMAX无线通信技术的现状,对中国网通在某区域试点的规划以及应用时应注意的问题进行了探讨. 相似文献