全文获取类型
收费全文 | 4421篇 |
免费 | 210篇 |
国内免费 | 198篇 |
专业分类
电工技术 | 265篇 |
综合类 | 236篇 |
化学工业 | 26篇 |
金属工艺 | 55篇 |
机械仪表 | 360篇 |
建筑科学 | 210篇 |
矿业工程 | 40篇 |
能源动力 | 24篇 |
轻工业 | 44篇 |
水利工程 | 14篇 |
石油天然气 | 15篇 |
武器工业 | 53篇 |
无线电 | 1019篇 |
一般工业技术 | 76篇 |
冶金工业 | 81篇 |
原子能技术 | 16篇 |
自动化技术 | 2295篇 |
出版年
2024年 | 7篇 |
2023年 | 27篇 |
2022年 | 42篇 |
2021年 | 42篇 |
2020年 | 65篇 |
2019年 | 36篇 |
2018年 | 49篇 |
2017年 | 56篇 |
2016年 | 73篇 |
2015年 | 90篇 |
2014年 | 210篇 |
2013年 | 157篇 |
2012年 | 255篇 |
2011年 | 312篇 |
2010年 | 213篇 |
2009年 | 207篇 |
2008年 | 229篇 |
2007年 | 357篇 |
2006年 | 295篇 |
2005年 | 313篇 |
2004年 | 268篇 |
2003年 | 260篇 |
2002年 | 215篇 |
2001年 | 161篇 |
2000年 | 117篇 |
1999年 | 135篇 |
1998年 | 122篇 |
1997年 | 93篇 |
1996年 | 80篇 |
1995年 | 63篇 |
1994年 | 43篇 |
1993年 | 52篇 |
1992年 | 34篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 28篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1975年 | 9篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有4829条查询结果,搜索用时 15 毫秒
91.
混沌保密通信是当今研究热门课题之一。本文就混沌系统应用于保密通信中的基本理论, 编码方式和密钥等内容作一简要讨论, 并采用一次一密密码体制,用损耗调制CO2 激光器混沌系统的输出作为密钥分别对文本文件、图形文件进行加密和解密。这种一次一密加密方式是不可破译的 相似文献
92.
This communique presents forced second-order consensus protocols with communication time-delays for the network of agents with double integrator dynamics and gives a measure of the robustness of the protocols to the communication time-delays. By employing a frequency domain method, it is proven that the forced consensus is achieved asymptotically for appropriate time-delay if the network is connected. Particularly, the maximum fixed time-delay that can be tolerated by the network is found. The forced consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results. 相似文献
93.
针对传统人工抄表计量方式存在的不足,利用先进的移动通讯技术和动态Web技术研制开发了新一代油田计量站原油分站计量系统,实现了计量数据的自动采集、无线远程传输和网络发布共享。 相似文献
94.
Porter sites have tried to increase their business potentials by helping users easily engage in diverse online activities such as search, entertainment, online communities, and others. Knowledge search engine is one of the most successful killer applications increasing user loyalty. However, most studies have independently focused on search engine technology such as search keyword algorithm, presentation of information and user characteristics such as cognitive style, search experiences, and skill levels. However, these previous studies lack an integrated understanding of causal links among critical factors predicting user motives and intention involving more situation-specific user characteristics. To fill these gaps in the literature, the present study focuses on whether knowledge characteristics such as specialization, preciseness, and diversity, and system characteristics such as interactivity, responsiveness, and communication richness are important in forming user motives and intention. The present study also identifies a moderating role of epistemic curiosity in the links between motives and intention. Two hundred and fifty-five data from Korean university students confirmed that knowledge and services characteristics such as specialty, preciseness, diversity, communication richness improve user motives, which have a positive impact on intention. Epistemic curiosity has a moderating effect on the links between motives and intention. Theoretical and practical implications are discussed in conclusion. 相似文献
95.
随着以太网技术的发展,远程电源监控在各个领域应用越来越广泛。提出了以以太网作为远程终端和前端服务器通讯的介质,对远程嵌入式电源进行控制技术的研究。根据远程客户端采集信息,具体分析得出了对远程电源的控制要求,通过数据库作为接口,和服务器控制程序进行通信,服务器程序通过循环检测数据库的信息,更新控制信息的变化,利用TCP/IP协议,通过以太局域网发送控制信号,实现对远程终端嵌入式电源的控制。设计了具体的信息采集流程,得到与实际需求相符合的控制要求。 相似文献
96.
扩频通信是现代通信系统中新的通信方式,它具有较强的抗干扰、抗衰落和抗多径性能,频谱利用率高的特点。扩展频谱通信是一种将信息的带宽扩展很多倍进行通信的技术,近年来在现代科技的许多领域中,应用非常广泛。着重叙述了扩频通信的工作原理、特点、及其发展应用。 相似文献
97.
98.
In previous works, the agent communication always takes place randomly through the whole agents distributed area, and all agents are treated equally in the communication process. However, the real communication is always imbalanced: communication in some places of the system may be very busy and the communication resources are insufficient, whereas in other places the communication may be very idle and the communication resources are redundant. To make up the shortage of related works, this paper presents a cluster partition-based communication model for multiagents. In the presented model, agents are divided into some clusters according to their communication frequencies; in each cluster, one agent is set to be hub-agent which carries the information of other agents within the cluster. With the presented model, the communication costs within the same cluster is lower than the one among different clusters because agents have closer distances within the same cluster; moreover, many real communication processes may take place within clusters since the clusters are partitioned according to the communication frequencies among agents. Therefore, the communication time and costs can be reduced by adopting our model. Finally, the advantage of our model is proved by a series of experiments. 相似文献
99.
100.
针对配用电领域的接入层通信特点,提出了融合多种通信方式的配用电通信平台实现技术.分析了通信接入平台的功能模型,实现不同通信类型终端的统一接入与管理.实践证明,采用该技术可灵活组建和部署通信接入方式,从而满足了配用电自动化系统的各种业务综合接入需求. 相似文献