全文获取类型
收费全文 | 57789篇 |
免费 | 6137篇 |
国内免费 | 4681篇 |
专业分类
电工技术 | 5017篇 |
技术理论 | 12篇 |
综合类 | 7199篇 |
化学工业 | 1612篇 |
金属工艺 | 756篇 |
机械仪表 | 3812篇 |
建筑科学 | 4068篇 |
矿业工程 | 1819篇 |
能源动力 | 944篇 |
轻工业 | 1066篇 |
水利工程 | 2567篇 |
石油天然气 | 1081篇 |
武器工业 | 1098篇 |
无线电 | 8432篇 |
一般工业技术 | 3490篇 |
冶金工业 | 2423篇 |
原子能技术 | 602篇 |
自动化技术 | 22609篇 |
出版年
2024年 | 221篇 |
2023年 | 594篇 |
2022年 | 1233篇 |
2021年 | 1490篇 |
2020年 | 1672篇 |
2019年 | 1260篇 |
2018年 | 1182篇 |
2017年 | 1635篇 |
2016年 | 1974篇 |
2015年 | 2127篇 |
2014年 | 3918篇 |
2013年 | 3697篇 |
2012年 | 4452篇 |
2011年 | 4536篇 |
2010年 | 3486篇 |
2009年 | 3747篇 |
2008年 | 3916篇 |
2007年 | 4334篇 |
2006年 | 3982篇 |
2005年 | 3521篇 |
2004年 | 2988篇 |
2003年 | 2725篇 |
2002年 | 2009篇 |
2001年 | 1669篇 |
2000年 | 1336篇 |
1999年 | 972篇 |
1998年 | 692篇 |
1997年 | 588篇 |
1996年 | 496篇 |
1995年 | 372篇 |
1994年 | 357篇 |
1993年 | 249篇 |
1992年 | 209篇 |
1991年 | 162篇 |
1990年 | 83篇 |
1989年 | 113篇 |
1988年 | 88篇 |
1987年 | 50篇 |
1986年 | 53篇 |
1985年 | 45篇 |
1984年 | 57篇 |
1983年 | 36篇 |
1982年 | 26篇 |
1981年 | 22篇 |
1980年 | 24篇 |
1979年 | 23篇 |
1966年 | 15篇 |
1965年 | 13篇 |
1964年 | 31篇 |
1958年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
《国际互联网参考资料服务季刊》2013,18(2):75-96
Multi-user Data base (MUD) technology, and its object-oriented descendant (MOO), is one of the most exciting tools to surface on the Internet, and offers libraries and librarians a unique opportunity to participate in creating user-friendly standardized interfaces to many of our most frequently used resources. These resources include those we access through the Internet already, using gopher, telnet, WWW, and FTP, and also those proprietary databases that we currently access through leased lines such as OCLC First Search, Prism, DIALOG, and many others. MOO technology is already being used successfully to create user-extensible collaborative professional environments for educators, astronomers, and computer network systems administrators. With the growing relevance of the Internet for libraries and other information professionals, it behooves the library community to engage those emerging technologies which will aloow us to interface most effectively with the Internet and its many resources, with the proprietary databases which we depend on, and with one another. 相似文献
52.
Academic librarians have shared their experiences with tablet computers, but few examine how librarians use tablets in their instruction design. While the education literature provides technology integration models, the nature of library instruction requires adapting these models to the library classroom. After reviewing literature related to tablets in library instruction and a number of technology integration frameworks, this article demonstrates an application of the Substitution, Augmentation, Modification, Redefinition framework to analyze observations of an iPad-equipped classroom at a university library. Demonstrating this use of a framework provides an approach to technology integration and continues the discussion about tablets’ potential to promote innovative pedagogy. 相似文献
53.
Michael Breaks 《New Review of Information Networking》2013,18(2):67-68
The process undertaken by an information seeker, in order to form relevance decisions regarding documents, is defined as “Document Triage.” To better facilitate users’ needs in their triage activities, interactive interfaces have begun to evolve within on-line academic repositories. In order to complement current work on interface design and interaction, and produce custom guidelines to inform the creation of triage interfaces, we examine how interfaces that alter the document presentation and structure affect information seekers’ visual and navigational attention. We present a set of heuristics for both creating and evaluating such interfaces. 相似文献
54.
随着网络技术在医院的应用,其安全性日益受到重视。首先结合军队医院信息系统网络应用的特点,从硬件系统、软件系统、环境因素、人为因素等方面分析该网络系统的安全性;最后研究该网络系统安全可能造成的威胁,并提出安全应对措施。 相似文献
55.
宋三华 《数字社区&智能家居》2009,(36)
RSS是基于XML的信息聚合技术,它使信息能够迅速、及时的传递给用户。该文主要介绍了RSS技术的基本概念及特点,然后基于该技术特点,具体探讨了该技术在网络教育上的应用。 相似文献
56.
小城镇综合地理信息系统的设计与开发 总被引:2,自引:2,他引:0
针对小城镇管理的现状和发展需求,结合小城镇的经济承受能力和科技力量,采用组件式GIS与可视化开发语言的集成二次开发方式,设计和开发了实用的小城镇综合地理信息系统.介绍了系统的技术框架,以其中的土壤资源管理子系统为例说明系统的开发过程,讨论了系统建设需要解决的几项关键问题.通过该系统可实现小城镇的资源、规划管理及工业、农业、商业,税务.交通等的统计、查询、分析及决策功能,同时可提供相应的图文资料. 相似文献
57.
介绍针对利用网络获取的期刊目次信息,运用Microsoft Visual Basic编程语言,实现期刊目次信息向用户自动推送的完全自动化。不仪可以将文献工作人员从以前繁琐的手动工作中解放出来,还使用户享受到便捷的目次报道服务。介绍期刊目次信息自动推送系统的设计思想、工作流程及实现方法。 相似文献
58.
In this paper, we address the problem of agent loss in vehicle formations and sensor networks via two separate approaches: (1) perform a ‘self‐repair’ operation in the event of agent loss to recover desirable information architecture properties or (2) introduce robustness into the information architecture a priori such that agent loss does not destroy desirable properties. We model the information architecture as a graph G(V, E), where V is a set of vertices representing the agents and E is a set of edges representing information flow amongst the agents. We focus on two properties of the graph called rigidity and global rigidity, which are required for formation shape maintenance and sensor network self‐localization, respectively. For the self‐repair approach, we show that while previous results permit local repair involving only neighbours of the lost agent, the repair cannot always be implemented using only local information. We present new results that can be applied to make the local repair using only local information. We describe implementation and illustrate with algorithms and examples. For the robustness approach, we investigate the structure of graphs with the property that rigidity or global rigidity is preserved after removing any single vertex (we call the property as 2‐vertex‐rigidity or 2‐vertex‐global‐rigidity, respectively). Information architectures with such properties would allow formation shape maintenance or self‐localization to be performed even in the event of agent failure. We review a characterization of a class of 2‐vertex‐rigidity and develop a separate class, making significant strides towards a complete characterization. We also present a characterization of a class of 2‐vertex‐global‐rigidity. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
59.
Chaoqing Yu Alan M. MacEachren Donna J. Peuquet Brent Yarnal 《Environmental Modelling & Software》2009,24(12):1501-1512
Recent natural disasters indicate that modern technologies for environmental monitoring, modeling, and forecasting are not well integrated with cross-level social responses in many hazard-management systems. This research addresses this problem through a Java-based multi-agent prototype system, GeoAgent-based Knowledge System (GeoAgentKS). This system allows: (1) computer representation of institutional regulations and behavioral rules used by multiple social institutions and individuals in cross-level human–environment interactions, (2) integration of this representation with scientific modeling of dynamic hazard development, and (3) application of automated reasoning that suggests to users the appropriate actions for supporting cooperative social responses. This paper demonstrates the software architecture of GeoAgentKS and presents such an integrated approach by modeling the drought management processes in Central Pennsylvania, USA. The results show that it is possible to use GeoAgentKS to represent multilevel human–environment interactions and to use those interactions as input to decision making in hazard management. 相似文献
60.
DU Jia-li LIU Yuan-yuan YU Ping-fang 《通讯和计算机》2009,6(7):68-78
By means of analysis of artificial intervention in ready-retrieved text, training set used to compare with new texts from large-scale real texts corpus is provided. It is based on the data-originated presentation of training set that a special formula to calculate semantic cohesion between new texts and training set is devised. The semantic cohesion of new text is the average value of semantic evaluation of all elements involved, and semantic evaluation of an element depends on its semantic relevance with the training set and on the semantic ratio of its domain to synonymous domain. In terms of empirical verification a conclusion is drawn that semantic cohesion is the key measurement standard of textual retrieval. Despite the advantages of textual retrieval, limitations of formula-raised condition and analyst's accomplishments make the analysis involved in this paper imperfect. 相似文献