全文获取类型
收费全文 | 17505篇 |
免费 | 2049篇 |
国内免费 | 1267篇 |
专业分类
电工技术 | 2156篇 |
技术理论 | 1篇 |
综合类 | 2127篇 |
化学工业 | 722篇 |
金属工艺 | 301篇 |
机械仪表 | 2486篇 |
建筑科学 | 896篇 |
矿业工程 | 495篇 |
能源动力 | 200篇 |
轻工业 | 372篇 |
水利工程 | 241篇 |
石油天然气 | 585篇 |
武器工业 | 315篇 |
无线电 | 2121篇 |
一般工业技术 | 1054篇 |
冶金工业 | 251篇 |
原子能技术 | 103篇 |
自动化技术 | 6395篇 |
出版年
2024年 | 104篇 |
2023年 | 247篇 |
2022年 | 486篇 |
2021年 | 556篇 |
2020年 | 580篇 |
2019年 | 427篇 |
2018年 | 395篇 |
2017年 | 476篇 |
2016年 | 540篇 |
2015年 | 714篇 |
2014年 | 1134篇 |
2013年 | 932篇 |
2012年 | 1310篇 |
2011年 | 1530篇 |
2010年 | 1143篇 |
2009年 | 1200篇 |
2008年 | 1201篇 |
2007年 | 1422篇 |
2006年 | 1211篇 |
2005年 | 1130篇 |
2004年 | 979篇 |
2003年 | 746篇 |
2002年 | 640篇 |
2001年 | 512篇 |
2000年 | 386篇 |
1999年 | 238篇 |
1998年 | 139篇 |
1997年 | 112篇 |
1996年 | 102篇 |
1995年 | 77篇 |
1994年 | 31篇 |
1993年 | 24篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 5篇 |
1957年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
AbstractIndustry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing. 相似文献
2.
ABSTRACT The concept of digital game-based learning (DGBL) evolves rapidly together with technological enhancements of virtual reality (VR) and smart phones. However, the mental workload (MWL) that VR-training applications demand and motivational qualities originating from user experience (UX) should be identified in order to create effective and enjoyable training/learning challenges that fit with individual users’ capabilities. This study examined the effects of reality-based interaction (RBI) and VR on measures of student motivation and MWL, in a mental arithmetic game for secondary school pupils. In a randomised controlled trial with sixty school children, a mental arithmetic game was tested with three different interaction and two different presentation methods – VR RBI, VR head-mounted-display tapping and tablet flick-gesture. Results found a significant effect of RBI on MWL but no differences in enjoyment of training were found between VR-experience and tablet training-experience. In fact, adding the gaming-context to the mental arithmetic task created an enjoyable, motivating experience regardless of presentation or interaction-style. 相似文献
3.
4.
5.
6.
A kind of complex additive mainly containing Al, Mg, F, and O was prepared. The synthetical performances of the property-modified prebaked anodes containing additives were tested in laboratory. On the basis of ideal testing results obtained, a large number of industrial prebaked property-modified anodes are prepared in a large-scale aluminum company. Further more, they are all used in 160 kA prebaked anode aluminum electrolysis cells. The statistic result show that, compared with common anodes, the property-modified ones enhance current by 11.6 kg per ton aluminum averagely. 相似文献
7.
图纸数据是企业间合作需交换的一种重要的信息。本文分析了虚拟企业环境下企业之间交换图纸数据的要求,提出了一种具体的解决方案,并给出实例。 相似文献
8.
9.
薄板坯连铸连轧工艺对铌微合金化高强度钢组织和性能的影响 总被引:1,自引:0,他引:1
首先建立薄板坯连铸连轧工艺的试验室模拟技术,并运用该模拟技术,研究薄板坯连铸连轧工艺(CSP)和传统板坯再加热工艺(TRP)两种工艺对铌微合金化高强度钢的显微组织和力学性能的影响。研究结果表明:CSP钢的晶粒细化效果不如TRP钢,两者的平均铁素体晶粒尺寸分别为8.17μm和6.30μm。在CSP试验钢板中铌的析出量较大,特别是在铁素体中细小颗粒的铌的析出物较多,沉淀强化效果较强。CSP试验钢的σ0.5和σb分别较TRP工艺低约40MPa和约25MPa,同时其低温冲击韧性较好,FATT温度较低。 相似文献
10.