全文获取类型
收费全文 | 18811篇 |
免费 | 795篇 |
国内免费 | 771篇 |
专业分类
电工技术 | 420篇 |
技术理论 | 2篇 |
综合类 | 1134篇 |
化学工业 | 884篇 |
金属工艺 | 442篇 |
机械仪表 | 1301篇 |
建筑科学 | 1711篇 |
矿业工程 | 457篇 |
能源动力 | 361篇 |
轻工业 | 655篇 |
水利工程 | 156篇 |
石油天然气 | 394篇 |
武器工业 | 120篇 |
无线电 | 2008篇 |
一般工业技术 | 736篇 |
冶金工业 | 536篇 |
原子能技术 | 60篇 |
自动化技术 | 9000篇 |
出版年
2024年 | 25篇 |
2023年 | 153篇 |
2022年 | 206篇 |
2021年 | 350篇 |
2020年 | 430篇 |
2019年 | 305篇 |
2018年 | 263篇 |
2017年 | 348篇 |
2016年 | 477篇 |
2015年 | 447篇 |
2014年 | 1060篇 |
2013年 | 846篇 |
2012年 | 1073篇 |
2011年 | 1535篇 |
2010年 | 1077篇 |
2009年 | 943篇 |
2008年 | 1120篇 |
2007年 | 1248篇 |
2006年 | 1276篇 |
2005年 | 1140篇 |
2004年 | 942篇 |
2003年 | 951篇 |
2002年 | 793篇 |
2001年 | 675篇 |
2000年 | 503篇 |
1999年 | 472篇 |
1998年 | 381篇 |
1997年 | 268篇 |
1996年 | 213篇 |
1995年 | 197篇 |
1994年 | 124篇 |
1993年 | 88篇 |
1992年 | 60篇 |
1991年 | 64篇 |
1990年 | 44篇 |
1989年 | 47篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 32篇 |
1984年 | 27篇 |
1983年 | 21篇 |
1982年 | 18篇 |
1981年 | 24篇 |
1980年 | 18篇 |
1979年 | 12篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Abstract The purpose of this exploratory study was to investigate the influence of two individual characteristics (Web experience and academic focus) of adolescents on the Web perception, using off-line questionnaires (a Lickert response scale) constituted on the basis of a series of interviews. Questions concerned: perceptions about the nature of information found in the Web; 'strategies' of access to the interesting Internet sites and the reliability of different information resources (libraries, television, Web, etc.). Results lead to the assumption that adolescents with high Web experience became more critical, less confident and less enthusiastic than adolescents with low Web experience and that, in some dimensions, perceptions of literature students are different to those of science students. Even if some interesting results were obtained, further research is needed to explore users' perceptions related to individuals' characteristics and to determine the generalisability of the influences identified in this exploratory study. 相似文献
12.
13.
钢管内径光电检测装置 总被引:3,自引:0,他引:3
介绍了一种检测细长钢管内径的光电检测装置。该装置利用线阵CCD作传感器,采用8031单片机作为主控制。 相似文献
14.
针对中小型企业销售管理的现状,利用J2EE架构技术设计了面向中小型企业的销售管理信息系统,该系统具有良好的跨平台性和可移植性,并且经过测试运行,达到了预期的效果。 相似文献
15.
中国民航信息系统现状及发展展望 总被引:2,自引:0,他引:2
介绍了中国民航信息系统的现状和与实际业务需求的差距,接着从系统设计理念、核心系统、新系统新功能和信息系统整合等多个方面详细阐述了民航信息系统的发展思路,最后强调了建立新一代民航信息系统的紧迫性,具备很强的指导意义。 相似文献
16.
Non-redundant data clustering 总被引:6,自引:6,他引:0
Data clustering is a popular approach for automatically finding classes, concepts, or groups of patterns. In practice, this
discovery process should avoid redundancies with existing knowledge about class structures or groupings, and reveal novel,
previously unknown aspects of the data. In order to deal with this problem, we present an extension of the information bottleneck
framework, called coordinated conditional information bottleneck, which takes negative relevance information into account by maximizing a conditional mutual information score subject to
constraints. Algorithmically, one can apply an alternating optimization scheme that can be used in conjunction with different
types of numeric and non-numeric attributes. We discuss extensions of the technique to the tasks of semi-supervised classification
and enumeration of successive non-redundant clusterings. We present experimental results for applications in text mining and
computer vision. 相似文献
17.
安全:爆破工程永恒的主题——2001年重大拆除爆破工程回顾 总被引:19,自引:10,他引:9
通过对2001年我国重大拆除爆破工程的回顾,认为在提高大面积毫秒非电起爆网络可靠性,控制爆破震动、扬尘、噪声等环境影响,与机械清理配合,实现快速施工等方面取得了进展与突破;对几起爆破安全事故进行了初步分析.为保证拆除爆破工程安全,在加强理论研究、开展技术创新、建立科学有序的管理制度等方面提出了建议意见. 相似文献
18.
Using the Internet, “public” computing grids can be assembled using “volunteered” PCs. To achieve this, volunteers download and install a software application capable of sensing periods of low local processor activity. During such times, this program on the local PC downloads and processes a subset of the project's data. At the completion of processing, the results are uploaded to the project and the cycle repeats. 相似文献
19.
Merging uncertain information with semantic heterogeneity in XML 总被引:1,自引:1,他引:0
Semistructured information can be merged in a logic-based framework [6, 7]. This framework has been extended to deal with
uncertainty, in the form of probability values, degrees of beliefs, or necessity measures, associated with leaves (i.e. textentries)
in the XML documents [3]. In this paper we further extend this approach to modelling and merging uncertain information that
is defined at different levels of granularity of XML textentries, and to modelling and reasoning with XML documents that contain
semantically heterogeneous uncertain information on more complex elements in XML subtrees. We present the formal definitions
for modelling, propagating and merging semantically heterogeneous uncertain information and explain how they can be handled
using logic-based fusion techniques.
Anthony Hunter received a B.Sc. (1984) from the University of Bristol and an M.Sc. (1987) and Ph.D. (1992) from Imperial College, London.
He is currently a reader in the Department of Computer Science at University College London. His main research interests are:
Knowledge representation and reasoning, Analysing inconsistency, Argumentation, Default reasoning and Knowledge Fusion.
Weiru Liu is a senior lecturer at the School of Computer Science, Queen's University Belfast. She received her B.Sc. and M.Sc. degrees
in Computer Science from Jilin University, P.R China, and her Ph.D. degree in Artificial Intelligence from the University
of Edinburgh. Her main research interests include reasoning under uncertainty, knowledge representation and reasoning, uncertain
knowledge and information fusion, and knowledge discovery in databases. She has published over 50 journal and conference papers
in these areas. 相似文献
20.