全文获取类型
收费全文 | 1630篇 |
免费 | 127篇 |
国内免费 | 95篇 |
专业分类
电工技术 | 53篇 |
综合类 | 83篇 |
化学工业 | 16篇 |
金属工艺 | 2篇 |
机械仪表 | 39篇 |
建筑科学 | 15篇 |
能源动力 | 11篇 |
轻工业 | 15篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
武器工业 | 7篇 |
无线电 | 370篇 |
一般工业技术 | 32篇 |
冶金工业 | 17篇 |
原子能技术 | 1篇 |
自动化技术 | 1182篇 |
出版年
2024年 | 6篇 |
2023年 | 10篇 |
2022年 | 29篇 |
2021年 | 41篇 |
2020年 | 24篇 |
2019年 | 27篇 |
2018年 | 35篇 |
2017年 | 55篇 |
2016年 | 41篇 |
2015年 | 59篇 |
2014年 | 94篇 |
2013年 | 102篇 |
2012年 | 78篇 |
2011年 | 134篇 |
2010年 | 79篇 |
2009年 | 81篇 |
2008年 | 126篇 |
2007年 | 109篇 |
2006年 | 122篇 |
2005年 | 98篇 |
2004年 | 71篇 |
2003年 | 67篇 |
2002年 | 56篇 |
2001年 | 44篇 |
2000年 | 33篇 |
1999年 | 32篇 |
1998年 | 29篇 |
1997年 | 19篇 |
1996年 | 26篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1964年 | 1篇 |
排序方式: 共有1852条查询结果,搜索用时 0 毫秒
91.
A (t, n)-locally random reduction maps a problem instancex into a set of problem instancesy
1,...,y
n in such a way that it is easy to construct the answer tox from the answers toy
1,...,y
n, and yet the distribution ont-element subsets ofy
1,...,y
n depends only on |x|. In this paper we formalize such reductions and give improved methods for achieving them. Then we give a cryptographic application,
showing a new way to prove in perfect zero knowledge that committed bitsx
1,...,x
m satisfy some predicateQ. Unlike previous techniques for such perfect zero-knowledge proofs, ours uses an amount of communication that is bounded
by a fixed polynomial inm, regardless of the computational complexity ofQ.
These results were presented in preliminary form at the 10th Annual Crypto Conference, Santa Barbara, CA, August 1990. The
work of D. Beaver was done at Harvard University, supported in part by NSF Grant CCR-870-4513. The work of J. Kilian was done
at MIT and Harvard University, supported by an NSF postdoctoral fellowship. 相似文献
92.
在AdHoc网络技术的工程实现中,路由协议的选择以及硬件无线通信系统设计是要解决的两个关键环节。本文针对节点之间无等级结构的AdHoc网络,基于一种泛搜索路由协议进行AdHoc网络系统设计和实现。硬件通信设备采用单片机C8051F920控制无线数传模块的方案进行设计,按照搜索路由协议对单片机编写程序,继而组建AdHoc网络系统。通过对网络测试所得的数据结果进行分析,表明该路由协议能适应网路拓扑结构变化,准确地找到一条适合传输的路由,所设计通信系统满足AdHoc网络的基本特征。 相似文献
93.
LAN Zhou GUO Hong-xiang WU Jian LIN Jin-tong Key Laboratory of OCLT Ministry of Education Beijing University of Posts Telecommunications Beijing P.R. China 《中国邮电高校学报(英文版)》2005,12(2)
1IntroductionOptical Burst Switching (OBS)[1 ~4]provides a feasi-ble paradigm for Internet Protocol (IP) over Wave-length-Division Multiplexing ( WDM) integration[5 ~10],which has been the focus of intense investigation owingtoits flexibilityin utilizingthe terahertz bandwidth of asingle fiber andits capabilitytosupport transparent datatransmissions. However , with the emergence of allkinds of applications such as data ,voice ,the next-gen-eration network must also be designedto provide … 相似文献
94.
基于ATL的公平电子商务协议形式化分析 总被引:1,自引:0,他引:1
针对传统时序逻辑LTL,CTL及CTL*等把协议看成封闭系统进行分析的缺点,Kremer博士(2003)提出用一种基于博弈的ATL(Alternating-time Temporal Logic)方法分析公平电子商务协议并对几个典型的协议进行了公平性等方面的形式化分析。本文讨论了ATL逻辑及其在电子商务协议形式化分析中的应用,进一步扩展了Kremer博士的方法,使之在考虑公平性等特性的同时能够分析协议的安全性。最后本文用新方法对Zhou等人(1999)提出的 ZDB协议进行了严格的形式化分析,结果发现该协议在非保密通道下存在两个可能的攻击:保密信息泄露和重放攻击。 相似文献
95.
96.
详尽地分析了几种常用于WDM网的数据分组传输控制协议,然后,介绍了一种通过划分用户能量高低来消除分组冲突的协议──俘获ALOHA控制协议,并在此协议基础上,提出了一种假想ALOHA协议,为提高WDM网的吞吐量及降低信息传播时延提供了新的思路。 相似文献
97.
网络层路由遭受的攻击可归为:哄骗、篡改或重放路由信息、选择性转发、Sinkhole攻击、Sybil攻击、Wormholes攻击、Flooding攻击、应答欺骗.从效果上看,一种是直接对数据进行攻击,另一种是对路由拓扑结构的攻击.针对各种攻击,提出了外/内部攻击的对策. 相似文献
98.
The impact of MAC parameters on the performance of 802.15.4 PAN 总被引:1,自引:0,他引:1
The operation of a personal area network, operating under the IEEE Standard 802.15.4 in the beacon enabled mode, is analyzed using the theory of discrete time Markov chains and M/G/1/K queues. The model includes the impact of different parameters such as packet arrival rate, number of stations, station’s buffer size, packet size, and inactive period between the beacons. We have derived several important performance parameters such as probability of access, probability that medium is idle, queue length distribution in the device, and probability distribution of the packet service time. Some important conclusions regarding the implementation of 802.15.4 networks and compatible network devices are outlined. 相似文献
99.
There has been an escalation in deployment and research of wireless mesh networks by both the business community and academia in the last few years. Their attractive characteristics include low deployment cost, a low‐cost option to extend network coverage and ease of maintenance due to their self‐healing properties. Multiple routes exist between the sender and receiver nodes because of the mesh layout that ensures network connectivity even when node or link failures occur. Recent advances among others include routing metrics, optimum routing, security, scheduling, cross‐layer designs and physical layer techniques. However, there are still challenges in wireless mesh networks as discussed in this paper that need to be addressed. Cross‐layer design allows information from adjacent and non‐adjacent layers to be used at a particular layer for performance improvement. This paper presents a survey of cross‐layer protocol design approaches applied to the IEEE 802.11 standards for wireless multi‐hop mesh networks that have been proposed over the last few years for improved performance. We summarize the current research efforts in cross‐layer protocol design using the IEEE 802.11 standard in identifying unsolved issues that are a promising avenue to further research. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献