全文获取类型
收费全文 | 5649篇 |
免费 | 223篇 |
国内免费 | 365篇 |
专业分类
电工技术 | 156篇 |
综合类 | 241篇 |
化学工业 | 60篇 |
金属工艺 | 25篇 |
机械仪表 | 111篇 |
建筑科学 | 150篇 |
矿业工程 | 66篇 |
能源动力 | 89篇 |
轻工业 | 44篇 |
水利工程 | 15篇 |
石油天然气 | 24篇 |
武器工业 | 27篇 |
无线电 | 770篇 |
一般工业技术 | 119篇 |
冶金工业 | 37篇 |
原子能技术 | 15篇 |
自动化技术 | 4288篇 |
出版年
2024年 | 9篇 |
2023年 | 44篇 |
2022年 | 69篇 |
2021年 | 64篇 |
2020年 | 62篇 |
2019年 | 37篇 |
2018年 | 45篇 |
2017年 | 69篇 |
2016年 | 109篇 |
2015年 | 105篇 |
2014年 | 372篇 |
2013年 | 276篇 |
2012年 | 367篇 |
2011年 | 598篇 |
2010年 | 397篇 |
2009年 | 324篇 |
2008年 | 391篇 |
2007年 | 535篇 |
2006年 | 449篇 |
2005年 | 459篇 |
2004年 | 335篇 |
2003年 | 306篇 |
2002年 | 244篇 |
2001年 | 164篇 |
2000年 | 114篇 |
1999年 | 53篇 |
1998年 | 49篇 |
1997年 | 30篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 24篇 |
1993年 | 16篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有6237条查询结果,搜索用时 0 毫秒
1.
The ability to detect gun and gun held in hand or other body parts is a typical human skill. The same problem presents an imperative task for computer vision system. Automatic observer independent detection of hand held gun or gun held in the other body part, whether it is visible or concealed, provides enhance security in vulnerable places and initiates appropriate action there. Compare to the automatic object detection systems, automatic detection of gun has very few successful attempts. In the present scope of this paper, we present an extensive survey on automatic detection of gun and define a taxonomy for this particular detection system. We also describe the inherent difficulties related with this problem. In this survey of published papers, we examine different approaches used in state-of-the-art attempts and compare performances of these approaches. Finally, this paper concludes pointing to the possible research gaps in related fields. 相似文献
2.
Smartphones are being used and relied on by people more than ever before. The open connectivity brings with it great convenience and leads to a variety of risks that cannot be overlooked. Smartphone vendors, security policy designers, and security application providers have put a variety of practical efforts to secure smartphones, and researchers have conducted extensive research on threat sources, security techniques, and user security behaviors. Regrettably, smartphone users do not pay enough attention to mobile security, making many efforts futile. This study identifies this gap between technology affordance and user requirements, and attempts to investigate the asymmetric perceptions toward security features between developers and users, between users and users, as well as between different security features. These asymmetric perceptions include perceptions of quality, perceptions of importance, and perceptions of satisfaction. After scoping the range of smartphone security features, this study conducts an improved Kano-based method and exhaustively analyzes the 245 collected samples using correspondence analysis and importance satisfaction analysis. The 14 security features of the smartphone are divided into four Kano quality types and the perceived quality differences between developers and users are compared. Correspondence analysis is utilized to capture the relationship between the perceived importance of security features across different groups of respondents, and results of importance-satisfaction analysis provide the basis for the developmental path and resource reallocation strategy of security features. This article offers new insights for researchers as well as practitioners of smartphone security. 相似文献
3.
This article presents a new method for pairing devices securely. The commitment-based authentication uses a fuzzy secret that the devices only know approximately. Its novel feature is time-based opening of commitments in a single round. We also introduce a new source for the fuzzy secret: synchronized drawing with two fingers of the same hand on two touch screens or surfaces. The drawings are encoded as strings and compared with an edit-distance metric. A prototype implementation of this surprisingly simple and natural pairing mechanism shows that it accurately differentiates between true positives and man-in-the-middle attackers. 相似文献
4.
随着社会的不断发展,矿产资源为我国带来了巨大的经济效益,并在社会经济发展中占有重要的地位。但在矿山资源开发的过程中,威胁人身安全的事故经常发生。因此,本文对探矿工程安全措施进行了研究和分析。 相似文献
5.
This work considers the problem of increasing the performance of the ciphers based on Data-Dependent (DD) operations (DDO)
for VLSI implementations. New minimum size primitives are proposed to design DDOs. Using advanced DDOs instead of DD permutations
(DDP) in the DDP-based iterative ciphers Cobra-H64 and Cobra-H128 the number of rounds has been significantly reduced yielding
enhancement of the “performance per cost” value and retaining security at the level of indistinguishability from a random
transformation. To obtain further enhancement of this parameter a new crypto-scheme based on the advanced DDOs is proposed.
The FPGA implementation of the proposed crypto-scheme achieves higher throughput value and minimizes the allocated resources
than the conventional designs. Design of the DDO boxes of different orders is considered and their ASIC implementation is
estimated. 相似文献
6.
本文描述数据访问组件MDAC(Microsoft Data Access Components)的结构与编程接口,分析了MDAC缓冲区溢出安全漏洞的原因,最后阐述了最新MDAC2.8的安全特征. 相似文献
7.
文章介绍了SOC设计流程,智能I/O处理器组成,在开发该处理器对VHDL源代码的优化问题。 相似文献
8.
WLAN的安全性设计 总被引:6,自引:0,他引:6
胡伏湘 《计算机应用与软件》2003,20(10):94-96
本文分析了WLAN中存在的安全问题,并提出了相应的解决策略,对于WLAN的设计具有较高的参考价值。 相似文献
9.
在互联网服务中,即时通讯已成为了最流行的服务模式之一,人们对即时通讯的依赖程度也与日俱增。但是, 频频出现的病毒和黑客攻击使广大用户深受其害,即时通讯的安全问题也日益严峻。为了从根本上解决问题,本文对即时通讯软件的架构和协议进行了深入分析,目的是找出漏洞根源,给开发者和使用者提供防止漏洞的依据。 相似文献
10.
In these times of global change, many facility emphases are competing for limited resources. Competing factors include, but are not limited to, sustainable design or green buildings; security, hardening or force protection; accessibility; historic preservation; aesthetics; and functionality. Yet, unlimited resources are seldom, if ever, available to fulfill all of these competing requirements in private or public construction. The Georgia Institute of Technology designed a decision matrix to allow owners and planners to balance these competing requirements on a project-by-project basis and to document the rationale. 相似文献