全文获取类型
收费全文 | 22800篇 |
免费 | 2399篇 |
国内免费 | 1802篇 |
专业分类
电工技术 | 1780篇 |
技术理论 | 10篇 |
综合类 | 2877篇 |
化学工业 | 1020篇 |
金属工艺 | 444篇 |
机械仪表 | 1883篇 |
建筑科学 | 2011篇 |
矿业工程 | 525篇 |
能源动力 | 543篇 |
轻工业 | 457篇 |
水利工程 | 374篇 |
石油天然气 | 510篇 |
武器工业 | 197篇 |
无线电 | 2294篇 |
一般工业技术 | 2008篇 |
冶金工业 | 1038篇 |
原子能技术 | 75篇 |
自动化技术 | 8955篇 |
出版年
2024年 | 161篇 |
2023年 | 396篇 |
2022年 | 682篇 |
2021年 | 750篇 |
2020年 | 689篇 |
2019年 | 536篇 |
2018年 | 482篇 |
2017年 | 532篇 |
2016年 | 655篇 |
2015年 | 790篇 |
2014年 | 1375篇 |
2013年 | 1337篇 |
2012年 | 1501篇 |
2011年 | 1724篇 |
2010年 | 1443篇 |
2009年 | 1364篇 |
2008年 | 1433篇 |
2007年 | 1590篇 |
2006年 | 1505篇 |
2005年 | 1321篇 |
2004年 | 1207篇 |
2003年 | 1015篇 |
2002年 | 771篇 |
2001年 | 750篇 |
2000年 | 596篇 |
1999年 | 507篇 |
1998年 | 330篇 |
1997年 | 251篇 |
1996年 | 219篇 |
1995年 | 224篇 |
1994年 | 160篇 |
1993年 | 147篇 |
1992年 | 110篇 |
1991年 | 88篇 |
1990年 | 67篇 |
1989年 | 71篇 |
1988年 | 62篇 |
1987年 | 23篇 |
1986年 | 25篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1966年 | 4篇 |
1965年 | 4篇 |
1963年 | 5篇 |
1958年 | 4篇 |
1956年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
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
22.
移动式数据挖掘平台模型 总被引:1,自引:0,他引:1
本文提出了一种移动式网络海量数据挖掘平台,给出了数据挖掘任务的形式化描述,详细讨论了平台的体系结构、工作原理与流程。该平台克服了传统网络计算模式的缺陷,支持对异质、分散数据源和知识源的挖掘和检索,具有开放性、可伸缩性、灵活性、可扩展性、健壮性。 相似文献
23.
Fadwa T. Eljack Ahmed F. Abdelhady Mario R. Eden Frederico B. Gabriel Xiaoyun Qin Mahmoud M. El-Halwagi 《Computers & Chemical Engineering》2005,29(11-12):2304
Decoupling the constitutive equations from the balance and constraint equations allows for reformulating a conventional forward problem into two reverse problems. The first reverse problem is the reverse of a simulation problem, where the process model is solved in terms of the constitutive (synthesis/design) variables instead of the process variables, thus providing the synthesis/design targets. The second reverse problem (reverse property prediction) solves the constitutive equations to identify unit operations, operating conditions and/or products by matching the synthesis/design targets. Visualization of the problem is achieved by employing recently developed property clustering techniques, which allows a high-dimensional problem to be visualized in two or three dimensions. The clusters by definition satisfy intra-stream and inter-stream conservation through linear “mixing” rules, which allows for the development of consistent additive rules along with their ternary representation. 相似文献
24.
25.
Markus Stolze 《Knowledge》1994,7(4):271-273
System development is strongly influenced by the perspectives used by system developers. Current development methods for knowledge-based systems are based on an information processing perspectives of experts and users which has been criticized by a number of researchers. The paper argues that work-oriented development of knowledge-based systems requires the parallel use of multiple perspectives (including the information processing perspective), and that the use of any single perspective is potentially dangerous. As an example of the importance of using multiple perspectives, thepaper presents the situated action perspective, and shows how it complements the information processing perspective. 相似文献
26.
Guo Ya-kun Wen Xian-yun Institute of Hydraulic Research Chengdu University of Science Technology Chengdu P.R.China 《水动力学研究与进展(B辑)》1993,(1)
In this paper,using complex functional theory,the authors turn the potentialflow around the surface irregularities in a pressure conduit and semi-infinite platforms intoDirichlet problem.Based on Schwarz formula and by the application of Plemelj's formula,theauthors change the problem into the integration of a Cauchy boundary integral equation in theflow plane through the substitution of variables.Using numerical integration,the authors obtainthe velocity distribution and pressure coefficient along surface irregularities and platforms.Thephysical concept of this method is clear,the convergent speed is rapid and the computative effi-ciency is high.The calculated values agree well with the measured results.It is an effective andsimple method in solving potential flow. 相似文献
27.
本文主要根据电子整机的发展要求,从集成化、高性能和高可靠等三方面分析国外模似IC的发展,进而说明模拟IC总的发展趋势及其表现。最后指出,模拟IC正面临一个新的变革时期。 相似文献
28.
29.
产品数据管理系统数据库设计 总被引:1,自引:0,他引:1
工程数据库EDB(Engineering Database),是工程设计及制造领域中相互有关的数据所组成的集合,本文在详细分析工程数据库的特点及其实现方式的基础上,结合SF-PDM数据库设计,深入讨论了使用UML进行数据库概念设计和逻辑设计的方法与步骤,总结介绍了SF-PDM数据库物理设计的思路与相关实现过程。 相似文献
30.
Repeated reference creates strong expectations in addressees that a speaker will continue to use the same expression for the same object. The authors investigate the root reason for these expectations by comparing a cooperativeness-based account (Grice, 1975) with a simpler consistency-based account. In two eye-tracking experiments, the authors investigated the expectations underlying the effect of precedents on comprehension. The authors show that listeners expect speakers to be consistent in their use of expressions even when these expectations cannot be motivated by the assumption of cooperativeness. The authors conclude that though this phenomenon seems to be motivated by cooperativeness, listeners' expectation that speakers be consistent in their use of expressions is governed by a general expectation of consistency. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献