全文获取类型
收费全文 | 348篇 |
免费 | 13篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 13篇 |
综合类 | 17篇 |
化学工业 | 79篇 |
金属工艺 | 4篇 |
机械仪表 | 21篇 |
建筑科学 | 38篇 |
矿业工程 | 3篇 |
能源动力 | 7篇 |
轻工业 | 14篇 |
石油天然气 | 2篇 |
武器工业 | 7篇 |
无线电 | 28篇 |
一般工业技术 | 45篇 |
冶金工业 | 3篇 |
自动化技术 | 94篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 17篇 |
2013年 | 16篇 |
2012年 | 12篇 |
2011年 | 33篇 |
2010年 | 18篇 |
2009年 | 23篇 |
2008年 | 20篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 33篇 |
2004年 | 24篇 |
2003年 | 19篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有375条查询结果,搜索用时 15 毫秒
1.
We create a business as usual scenario for office equipment electricity use from industry forecasts of equipment sales, surveys of equipment densities by building type, measured data on wattage and usage by equipment type and projected lifetimes for equipment. We then calculate electricity used by building type and equipment type for Energy Star and advanced scenarios and explore the sensitivity of these results to variations in key input parameters. According to our analysis, the Energy Star programme will save the US almost US$1 billion annually starting in the year 2000, with minimal expenditure of public funds. 相似文献
2.
Eddie Cheng 《Information Sciences》2007,177(22):4877-4882
We prove that when linearly many vertices are deleted in a Cayley graph generated by a transposition tree, the resulting graph has a large connected component containing almost all remaining vertices. 相似文献
3.
4.
李广智 《气象水文海洋仪器》2005,(Z1)
找星仪是卫星地面站安装、调试、维修所必不可少的设备。旧的找星仪笨重、由于必须两人操作,很不方便。针对这些问题开发了便携式多功能找星仪。本文主要介绍了该设备的构成及其电路原理。 相似文献
5.
回顾重钢七厂连铸板坯星状裂纹导致轧制钢板表面产生龟裂缺陷、以及对钢坯产生星裂的机理的认识过程,借助国外在这方面的研究成果进行对比分析,认为控制板坯星裂的最重要技术措施是采用"结晶器软冷却”工艺、以及控制钢的铁素体势和铜当量。 相似文献
6.
p-(Iodomethyl)styrene was polymerized under the action of a radical initiator (AIBN). The polymerization proceeds with degenerative chain transfer and leads to well defined branched polymers with functional primary and secondary iodomethyl groups as revealed by NMR studies. The obtained polymer can be further used as macroinitiator for radical polymerization of styrene. This polymerization proceeds in controlled way to polystyrene star polymers with reactive groups at the end of their arms. The characterization of branched and star structures was performed by NMR and GPC with absolute molar mass detection (MALLS). 相似文献
7.
A novel ether connected epoxy star like polymer was synthesized by selective reaction of water soluble polyhydroxy fullerene (fullerenol) with a commercial grade cycloaliphatic epoxy resin (CY-230, Ciba Geigy) in heterogeneous medium at ambient alkaline condition using tetrabutylammonium hydroxide as phase transfer catalyst. The reaction went well in such conditions and the hydroxy groups of fullerenol underwent selective nucleophilic addition reaction with polar carbonyl groups of the epoxy resin with the formation of a hemiketal. The progress of the reaction was monitored by FTIR analysis of the product formed. The disappearance of characteristic FTIR bands of fullerenol (at 1593.2, 1381.2, and 1068 cm−1) and the typical carbonyl peak (at 1725 cm−1) of parent epoxy resin and also changes of broad hydroxy peak (at 3431 cm−1) of fullerenol into a sharp peak (at 3396.6 cm−1, indicating reduced hydrophilicity) in the reaction product clearly demonstrated the chemical attachment of the epoxy units to the fullerene core. Multiple epoxy units (about 8-10) were attached to fullerene core. Non-reactivity of fullerenol towards DGEBA epoxy resin (LY 556 Ciba Geigy) in similar conditions further supports our result. The thermal properties of the product were influenced by the presence of fullerenol and exhibits higher thermal stability compared to parent epoxy. A probable reaction mechanism for the reaction has also been discussed. 相似文献
8.
Kathleen Menzies Duncan Birrell Gordon Dunsire 《New Review of Information Networking》2013,18(2):92-140
This article reports on the key findings and implications of the Joint Information Systems Committee (JISC)-funded Online Catalogue and Repository Interoperability Study (OCRIS), a 3-month project which investigated the interoperability of Online Public Access Catalogues (OPACs) and Institutional Repositories (IRs) within UK universities. A series of detailed recommendations enumerate some of the ways in which they might begin to develop and support an interoperable systems landscape to the benefit of all key stakeholders. The project combined quantitative and qualitative research methods including an online questionnaire distributed to staff within 85 universities, desk research, and two case studies conducted at the Universities of Cambridge and Glasgow. 相似文献
9.
The quality of plane layout design of the disc cutters for the full-face rock tunnel boring machine (TBM) directly affects the balance of force distribution on the cutter head during the excavating. Various layout patterns have been adopted in practice during the layout design of the disc cutters. Considering the engineering technical requirements and the corresponding structure design requirements of the cutter head, this study formulates a nonlinear multi-objective mathematical model with multiple constraints for the disc cutters plane layout design, and analyses the characteristics of a multi-spiral layout pattern, a dynamic star layout pattern and a stochastic layout pattern. And then a genetic algorithm is employed to solve a disc cutters’ multi-spiral layout problem, and a cooperative co-evolutionary genetic algorithm (CCGA) is utilized to solve a disc cutters’ star or stochastic layout problems. The emphasis was put on the study of superiority of three different layout patterns. Finally, an instance of the disc cutters’ plane layout design was solved by the proposed methods using three different kinds of layout patterns. Experimental results showed the effectiveness of the method of combining the mathematical model with the algorithms, and the pros and cons of the three layout patterns. 相似文献
10.