全文获取类型
收费全文 | 1126篇 |
免费 | 75篇 |
专业分类
电工技术 | 19篇 |
综合类 | 17篇 |
化学工业 | 301篇 |
金属工艺 | 13篇 |
机械仪表 | 13篇 |
建筑科学 | 86篇 |
矿业工程 | 12篇 |
能源动力 | 14篇 |
轻工业 | 229篇 |
水利工程 | 18篇 |
石油天然气 | 2篇 |
无线电 | 37篇 |
一般工业技术 | 209篇 |
冶金工业 | 74篇 |
原子能技术 | 2篇 |
自动化技术 | 155篇 |
出版年
2024年 | 3篇 |
2023年 | 17篇 |
2022年 | 38篇 |
2021年 | 60篇 |
2020年 | 31篇 |
2019年 | 25篇 |
2018年 | 43篇 |
2017年 | 38篇 |
2016年 | 46篇 |
2015年 | 40篇 |
2014年 | 44篇 |
2013年 | 74篇 |
2012年 | 57篇 |
2011年 | 96篇 |
2010年 | 50篇 |
2009年 | 41篇 |
2008年 | 81篇 |
2007年 | 64篇 |
2006年 | 43篇 |
2005年 | 53篇 |
2004年 | 35篇 |
2003年 | 31篇 |
2002年 | 23篇 |
2001年 | 22篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1972年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有1201条查询结果,搜索用时 9 毫秒
101.
Silvia Apprich Özge Tirpanalan Johannes Hell Michael Reisinger Stefan Böhmdorfer Susanne Siebenhandl-Ehn Senad Novalin Wolfgang Kneifel 《LWT》2014
Wheat bran is multi-layered and consists of different cell types with different chemical compositions. The relatively high content of protein as well as the small amount of lignin is the key differentiator to other lignocellulose containing biomasses. Following the classical route of a biorefinery, bran may be disintegrated to a high extent and separated into fractions of high purity in order to build up new chemicals which serve as precursors for higher polymerized compounds. Secondly, bran contains substances that are per se valuables, but need to be further separated and purified. 相似文献
102.
Yasmeen Taleb Obaidat Susanne Heyden Ola Dahlblom Ghazi Abu-Farsakh Yahia Abdel-Jawad 《Construction and Building Materials》2011,25(2):591-597
This paper presents the results of an experimental study to investigate the behaviour of structurally damaged full-scale reinforced concrete beams retrofitted with CFRP laminates in shear or in flexure. The main variables considered were the internal reinforcement ratio, position of retrofitting and the length of CFRP. The experimental results, generally, indicate that beams retrofitted in shear and flexure by using CFRP laminates are structurally efficient and are restored to stiffness and strength values nearly equal to or greater than those of the control beams. It was found that the efficiency of the strengthening technique by CFRP in flexure varied depending on the length. The main failure mode in the experimental work was plate debonding in retrofitted beams. 相似文献
103.
Whereas the benefits of decomposing process models are obvious, the question what actually characterizes a ??good?? decomposition of a business process model has been given little attention to date. In addition, the process of decomposition itself is considered as being an ??art?? in literature. Our approach for achieving a ??good?? decomposition is Wand and Weber??s decomposition model for information systems. As a first step in our investigation we aim to explore in how far the decomposition model can be adapted for business process modelling at all. The potential this model might bear for evaluating decompositions of process models has been promoted in literature quite often, while a corresponding investigation is still missing. We address this gap by the following research. In the long term, we intend to establish guidelines for decomposing business process models in a structured way. 相似文献
104.
105.
106.
107.
108.
Susanne Lackner 《Water research》2009,43(14):3469-3478
Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG) chains with two different functional groups (-PEG-NH2 and -PEG-CH3). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed similar trends: biofilms on -PEG-NH2 modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface structure might be possible explanations of the superiority of the -PEG-NH2 modification. The success of the-PEG-NH2 modification was independent of the original surface and might, therefore, be used in wastewater treatment bioreactors to improve reactor performance by making biofilm formation more stable and predictable. 相似文献
109.
Which kind of instruction helps children aged 9–14 years interact efficiently with a mobile phone? Due to analogies between navigation in menu structures and the natural environment, three instructions providing different forms of spatial knowledge were under study: A step-by-step instruction featuring landmark knowledge of the menu functions to be selected, a diagram of the menu structure providing survey knowledge and a free exploration of the menu, also giving the children the opportunity to develop survey knowledge. Results show a superiority of the two instructions that provide survey knowledge, except for the youngest children aged 9–10 years. This group showed to have lower spatial abilities and is therefore presumably not able to understand and integrate this type of knowledge. For those very young children, the landmark information given in traditional step-by-step instructions is more helpful. It is concluded, that simple diagrams of the menu structure can help children from 11 years on to significantly ease their interaction with small menu driven devices. 相似文献
110.