全文获取类型
收费全文 | 51877篇 |
免费 | 7111篇 |
国内免费 | 5255篇 |
专业分类
电工技术 | 4716篇 |
技术理论 | 3篇 |
综合类 | 5809篇 |
化学工业 | 2772篇 |
金属工艺 | 1521篇 |
机械仪表 | 3247篇 |
建筑科学 | 1560篇 |
矿业工程 | 1034篇 |
能源动力 | 1412篇 |
轻工业 | 923篇 |
水利工程 | 878篇 |
石油天然气 | 901篇 |
武器工业 | 540篇 |
无线电 | 8674篇 |
一般工业技术 | 3325篇 |
冶金工业 | 1045篇 |
原子能技术 | 185篇 |
自动化技术 | 25698篇 |
出版年
2024年 | 427篇 |
2023年 | 1292篇 |
2022年 | 2175篇 |
2021年 | 2391篇 |
2020年 | 2441篇 |
2019年 | 1801篇 |
2018年 | 1451篇 |
2017年 | 1662篇 |
2016年 | 1741篇 |
2015年 | 1951篇 |
2014年 | 2731篇 |
2013年 | 3079篇 |
2012年 | 3300篇 |
2011年 | 3708篇 |
2010年 | 2907篇 |
2009年 | 3362篇 |
2008年 | 3674篇 |
2007年 | 3859篇 |
2006年 | 3258篇 |
2005年 | 2917篇 |
2004年 | 2442篇 |
2003年 | 2017篇 |
2002年 | 1729篇 |
2001年 | 1520篇 |
2000年 | 1324篇 |
1999年 | 1107篇 |
1998年 | 905篇 |
1997年 | 746篇 |
1996年 | 614篇 |
1995年 | 462篇 |
1994年 | 340篇 |
1993年 | 245篇 |
1992年 | 173篇 |
1991年 | 92篇 |
1990年 | 71篇 |
1989年 | 40篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 34篇 |
1985年 | 44篇 |
1984年 | 38篇 |
1983年 | 37篇 |
1982年 | 44篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1963年 | 3篇 |
1959年 | 4篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
51.
Efficient multicast search under delay and bandwidth constraints 总被引:1,自引:0,他引:1
The issue of a multicast search for a group of users is discussed in this study. Given the condition that the search is over
only after all the users in the group are found, this problem is called the Conference Call Search (CCS) problem. The goal
is to design efficient CCS strategies under delay and bandwidth constraints. While the problem of tracking a single user has
been addressed by many studies, to the best of our knowledge, this study is one of the first attempts to reduce the search
cost for multiple users. Moreover, as oppose to the single user tracking, for which one can always reduce the expected search
delay by increasing the expected search cost, for a multicast search the dependency between the delay and the search cost
is more complicated, as demonstrated in this study. We identify the key factors affecting the search efficiency, and the dependency
between them and the search delay. Our analysis shows that under tight bandwidth constraints, the CCS problem is NP-hard.
We therefore propose a search method that is not optimal, but has a low computational complexity. In addition, the proposed
strategy yields a low search delay as well as a low search cost. The performance of the proposed search strategy is superior
to the implementation of an optimal single user search on a group of users.
Amotz Bar-Noy received the B.Sc. degree in 1981 in Mathematics and Computer Science and the Ph.D. degree in 1987 in Computer Science, both
from the Hebrew University, Israel. From October 1987 to September 1989 he was a post-doc fellow in Stanford University, California.
From October 1989 to August 1996 he was a Research Staff Member with IBM T. J. Watson Research Center, New York. From February
1995 to September 2001 he was an associate Professor with the Electrical Engineering-Systems department of Tel Aviv University,
Israel. From September 1999 to December 2001 he was with AT research labs in New Jersey. Since February 2002 he is a Professor
with the Computer and Information Science Department of Brooklyn College - CUNY, Brooklyn New York.
Zohar Naor received the Ph.D. degree in Computer Science from Tel Aviv University, Tel Aviv, Israel, in 2000. Since 2003 he is with
the University of Haifa, Israel. His areas of interests include wireless networks, resource management of computer networks,
mobility, search strategies, and multiple access protocols. 相似文献
52.
53.
径向基函数神经网络的再学习算法及其应用 总被引:3,自引:1,他引:2
谭建辉 《微电子学与计算机》2006,23(5):115-117,120
为了应用径向基函数神经网络逐步地识别待研究系统,文章针对径向基函数神经网络的再学习算法开展了深入的研究.应用严格的数学推理方法,将径向基函数神经网络的再学习问题转化为矩阵求逆的附加运算.详细给出了径向基函数神经网络再学习算法中增加新训练样本和增加新基函数的数学公式,同时对如何获取新的训练样本进行了研究. 相似文献
54.
目前需求预测在整个印制电路板产业的生产活动控制中正扮演着越来越重要的角色。分析了影响印制电路板需求的因素和现有的预测方法,提出了一种适用于PCB产业需求预测的有效方法——遗传/BP—神经网络。实验表明该方法能够进一步改善印制电路板预测的准确度和减少生产成本的消耗。 相似文献
55.
56.
Christian Stephan Bernd 《AEUE-International Journal of Electronics and Communications》2006,60(1):20-24
Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented. 相似文献
57.
58.
59.
人工智能的原理及应用 总被引:7,自引:0,他引:7
介绍了人工智能的发展,并对改进的神经网络专家系统的优越性做了介绍,指出了神经网络专家系统广阔的应用前景及实现。 相似文献
60.
电力系统谐波检测的现状与发展 总被引:7,自引:0,他引:7
准确、实时地对电力系统谐波进行检测有着重要的意义。本文根据电力系统谐波测量的基本方法,对近年来电力系统谐波检测的新方法进行了分析和评述。最后对电力系统的谐波测量进行了总结并提出了看法。 相似文献