全文获取类型
收费全文 | 433篇 |
免费 | 18篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 55篇 |
金属工艺 | 3篇 |
机械仪表 | 8篇 |
建筑科学 | 7篇 |
能源动力 | 2篇 |
轻工业 | 36篇 |
水利工程 | 2篇 |
无线电 | 7篇 |
一般工业技术 | 209篇 |
冶金工业 | 100篇 |
原子能技术 | 1篇 |
自动化技术 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 2篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 26篇 |
2012年 | 14篇 |
2011年 | 19篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 24篇 |
2007年 | 8篇 |
2006年 | 16篇 |
2005年 | 5篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 27篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1943年 | 1篇 |
1939年 | 4篇 |
排序方式: 共有451条查询结果,搜索用时 156 毫秒
1.
2.
International scientific collaboration is very sensitive to political and economic changes in a country or a geopolitical region. Collaboration in research is reflected by the corresponding coauthorship of the published results which can be analysed with the help of bibliometric methods. Based on data from theScience Citation Index (SCI), the change of annual international coauthorship patterns ofBulgaria, Czechoslovakia, Hungary, Poland andRomania have been analysed for the periods 1981–1985 and 1984–1993, respectively. It is shown that international collaboration was not developing similarly in the countries under study. Whilst scientific communities of Hungary and Poland have already been opening in the early 80s, the international collaboration of the other East-European countries was still dominated by COMECON relations till 1989. As expected, since 1990 an increasing scientific collaboration with highly developed countries can be observed in all five countries. At the same time, scientific collaboration with the former communist countries shows a clear decline. The great share of international co-authorship links is some countries reflect various tendencies part of which are interpreted with the help of a cardiologic model. 相似文献
3.
Janine Glänzel Arnd Meyer Roman Unger Michael Bräunig Volker Wittstock Steffen Ihlenfeldt 《The International Journal of Advanced Manufacturing Technology》2017,88(5-8):1279-1288
A new interdisciplinary approach is discribed to identifying unknown parameters using an extended version of the known interval bisection method. This developed method is based on the use of finite elements for calibrating the simulation calculation. The resulting thermo-elastic deformations which occur in drilling processes with impaired cooling lubrication are to be used as correction values for tool positioning in the NC control. Based on the strong impact on workpiece temperature of machining, a simulation approach is presented for calculating the temperature fields and their thermo-elastic consequences. In addition, methods are presented to correct these effects. This paper particularly deals with the temperature fields of drilling operations. Special attention is paid to the technique employed for iterative numerical determination of the unknown heat flux η w and heat transfer coefficient \(\bar {\gamma }\) values. Finally, the data obtained from experiments are compared with those achieved by numerical simulation in order to verify the efficiency of simulation and determination of parameters. 相似文献
4.
Felix Schmutzler Christopher Zschiesche Juliane Titus David Poppitz Jens Freiding Rainer Rakoczy Andreas Reitzmann Roger Gläser 《化学,工程师,技术》2021,93(6):981-989
The hydroisomerization of two long-chain n-alkane mixtures was investigated over bifunctional Pt/H-ZSM-5 catalysts before and after dealumination of preshaped zeolite/binder pellets. The hydroisomerization over the dealuminated catalysts leads to more isomers and less cracking products. Consequently, higher ratios of multi- to mono-branched isomerization products are formed as expected for large- rather than medium-pore zeolites. This indicates a higher availability of space in the vicinity of the active sites and provides an attractive route to make medium-pore zeolites suitable for upgrading higher boiling hydrocarbon feeds. 相似文献
5.
6.
Guido Böttcher Dennis Allerkamp Daniel Glöckner Franz-Erich Wolter 《The Visual computer》2008,24(10):911-922
Real-time cloth simulation involves many computational challenges to be solved, particularly in the context of haptic applications,
where high frame rates are necessary for obtaining a satisfying experience. In this paper, we present an interactive cloth
simulation system that offers a compromise between a realistic physics-based simulation of fabrics and a haptic application
meeting high requirements in terms of computation speed. Our system allows the user to interact with the fabric using two
fingers. The required performance of the system is achieved by introducing an intermediate layer responsible for the simulation
of the small part of the surface being in contact with the fingers. Additionally we separate the possible contact situations
into different cases, each being individually handled by a specialised contact algorithm.
相似文献
Franz-Erich WolterEmail: |
7.
Summary In the present paper, the evolution of publication activity and citation impact in Brazil is studied for the period 1991-2003.
Besides the analysis of trends in publication and citation patterns and of national publication profiles, an attempt is made
to find statistical evidences of the relation between international co-authorship and both research profile and citation impact
in the Latin American region. Despite similarities and strong co-publication links with the other countries in the region,
Brazil has nonetheless a specific research profile, and forms the largest potential in the region. 相似文献
8.
Hydrogenation of p‐Nitrophenol to p‐Aminophenol as a Test Reaction for the Catalytic Activity of Supported Pt Catalysts 下载免费PDF全文
Michael Goepel Majd Al‐Naji Patrick With Gerald Wagner Oliver Oeckler Dirk Enke Roger Gläser 《化学工程与技术》2014,37(3):551-554
Hydrogenation of p‐nitrophenol (PNP) to p‐aminophenol (PAP) using NaBH4 as a reducing agent was studied as a test reaction for determining the catalytic activity of supported Pt catalysts. The initial reaction rate, which is accessible within less than 10 min via online UV‐vis spectroscopy at room temperature, ambient pressure, and in water as solvent, was applied as measure for catalytic activity. For three Pt catalysts supported on porous SiO2, porous glass, and Al2O3, respectively, significant differences in the catalytic activity by almost one order of magnitude were observed. However, especially in the case of very active catalysts, limitations of the reaction by internal or external mass transfer have to be considered. 相似文献
9.
Ultrafiltration based purification strategies for surfactin produced by Bacillus subtilis LB5A using cassava wastewater as substrate 下载免费PDF全文
10.