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121.
Ad hoc网络中不同分布的随机功率控制 总被引:1,自引:1,他引:0
无线Ad hoc网络网络中的节能技术已经成为研究领域中的一个热点。采用随机功率控制的无线Ad hoc网络,节点之间成功传输概率及网络能耗与各节点发射功率的概率分布有关,分析并仿真了分别采用均匀分布、正线性分布、负线性分布、凸三角(类高斯)分布和凹三角分布的随机功率控制策略对Ad hoc网络通信成功概率和网络能耗的影响。结果表明采用正线性分布和类高斯分布的随机功率控制具有较优的性能。 相似文献
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下一代WLAN技术标准802.11ac/ad 总被引:1,自引:0,他引:1
基于IEEE802.11n标准的WLAN能够支持高达600 Mbit/s的传输速率,但在支持无线高清视频传输等高吞吐量无线数据业务时仍然会遇到瓶颈。面对这一挑战I,EEE已启动下一代WLAN技术标准802.11ac和802.11ad的制定工作,数据吞吐量将达到几个Gbit/s,能够更好地满足快速增长的市场需求。 相似文献
125.
在基于IEEE 802.11的移动自组织网络中,MAC(Medium Access Control)层提供了DCF(Distributed Coordinate Function)以控制节点对无线信道的争用.DCF包括了BEB (Binary Exponential Backoff)算法.该文对BEB的重要参数——竞争窗口CW(Contention Window)进行研究,通过随机建模,导出了竞争窗口长度的概率分布,并进行数值分析.研究结果可应用于IEEE 802.11移动自组织网络. 相似文献
126.
基于无线网络编码的信道利用率研究 总被引:1,自引:1,他引:0
为了使无线随机网络编码策略更好适用于较大数据量的传输要求,在无线信道的广播特性的基础上加入了将数据分块处理,并考虑了额外开销对信道利用率的影响.通过对分块传输模型的分析,确认信道利用率与分块的大小紧密相关,为了在通信前选择一个适当的分块大小以获得更高的信道利用率,给出了一种计算最优数据块大小的方法.仿真结果表明:该方法简单可行,使用该方法选择数据块大小后,信道利用率将十分接近其上限值. 相似文献
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分析了大学生使用微信“摇一摇”的现状,阐述了微信“摇一摇”对大学生的有利影响和不利影响,针对如何引导大学生正确合理使用微信“摇一摇”提出了相定的应对策略。 相似文献
129.
Many routing protocols and applications developed for ad hoc networks rely on location information of participating nodes. The exposure of such information, however, presents significant safety threats to the networks. In this paper, we investigate the problem of preventing an adversary from locating (and thus destroying) nodes based on their location information they disclose in communications. Our idea is to reduce location resolution to achieve a desired level of safety protection. We define the safety level of a geographic region to be the ratio of its area and the number of nodes inside it. The higher safety level a region has, the less attractive for an adversary to search over it for the nodes. When a node has to disclose its location, it can compute a cloaking box that meets a desired level of safety requirement and report that as its current location information. To implement this simple idea, there are several challenges. First, each cloaking box must be as small as possible in order to minimize the impact of reduced location resolution on the efficiency of network operating and applications. Second, nodes must be able to compute their cloaking boxes without having to reveal their accurate position. Finally, given a sequence of cloaking boxes, they must not be correlated to refine an area whose safety level is less than the requirement. Our research addresses these challenges with cost-effective solutions in the context of both stationary and mobile ad hoc networks. We evaluate the performance of our techniques through both mathematical analysis and simulation. In addition, we present a new geographic routing protocol which can work with blurred location information and evaluate the impact of location resolution reduction on the performance of this technique. 相似文献
130.
In this paper, we propose a policy-based framework for the management of wireless ad hoc networks and briefly describe a characteristics-based taxonomy that provides a platform to analyze and compare different architectural choices. We develop a solution suite that helps achieve our goal of a self-organizing, robust and efficient management system. One of the main contributions of this work is the prototype implementation and testing of the mechanisms and protocols comprising our framework in a multi-hop ad hoc network environment. Experiments are conducted using both an emulated ad hoc network testbed and a true wireless testbed. Degradation in management system performance is observed as the number of hops between a policy server and client increases. Our proposed k-hop clustering algorithm alleviates this problem by limiting the number of hops between a server and client. We demonstrate the operation of our prototype implementation, illustrating QoS management in a multi-domain ad hoc network environment using the proposed cluster management, redirection, and policy negotiation mechanisms. 相似文献