全文获取类型
收费全文 | 1096篇 |
免费 | 66篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 3篇 |
化学工业 | 254篇 |
金属工艺 | 30篇 |
机械仪表 | 17篇 |
建筑科学 | 111篇 |
矿业工程 | 2篇 |
能源动力 | 40篇 |
轻工业 | 50篇 |
水利工程 | 4篇 |
武器工业 | 1篇 |
无线电 | 75篇 |
一般工业技术 | 191篇 |
冶金工业 | 88篇 |
原子能技术 | 9篇 |
自动化技术 | 275篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 20篇 |
2021年 | 56篇 |
2020年 | 29篇 |
2019年 | 29篇 |
2018年 | 44篇 |
2017年 | 32篇 |
2016年 | 51篇 |
2015年 | 40篇 |
2014年 | 66篇 |
2013年 | 62篇 |
2012年 | 68篇 |
2011年 | 88篇 |
2010年 | 62篇 |
2009年 | 65篇 |
2008年 | 50篇 |
2007年 | 51篇 |
2006年 | 29篇 |
2005年 | 44篇 |
2004年 | 29篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 24篇 |
2000年 | 4篇 |
1999年 | 14篇 |
1998年 | 19篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 5篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1963年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有1163条查询结果,搜索用时 187 毫秒
991.
Manmohan DASS GOEL Vasant A. MATSAGAR Anil K. GUPTA Steffen MARBURG 《中国有色金属学会会刊》2013,23(4):1080-1089
With the increasing use of metal foams in various engineering applications, investigation of their dynamic behaviour under varying strain rate is necessary. Closed cell aluminium fly ash foam developed through liquid metallurgy route was investigated for its stress—strain behaviour at different strain rates ranging from 700 s?1 to 1950 s?1. The numerical model of split Hopkinson pressure bar (SHPB) was simulated using commercially available finite element code Abaqus/Explicit. Validation of numerical simulation was carried out using available experimental and numerical results. Full scale stress—strain curves were developed for various strain rates to study the effect of strain rate on compressive strength and energy absorption. The results showed that the closed cell aluminium fly ash foam is sensitive to strain rate. 相似文献
992.
In the combined laboratory and pilot plant investigation powder activated carbon dosing and inline coagulation were investigated for surface water from river Spree. The aim was to understand the fouling behaviour of this raw water and to understand and to identify strategies to minimize the irreversible fouling in this application. Trials with activated carbon showed significant differences in the adsorption of biopolymers on different types of carbon. Whereas the TOC removal was in the same range for both types the coarse carbon type showed very small removal of biopolymers. The effect of different types of coagulants, dosage and pH was investigated in a laboratory filtration set up. Samples were investigated by LC-OCD measurements for fractionation of DOC for raw water, flocculated water and permeate. The removal of biopolymers was possible with iron and alumina salts, however the alumina salts tend to remove humic acids as well and this results in a higher overall DOC removal. In the pilot plant the inline coagulation was investigated under actual site conditions. Whereas the results for the effect of coagulation and DOC removal were confirmed it turned out that aluminium coagulants give a significantly higher increase in differential pressure. The use of ferric coagulants at slightly acidic pH was thus identified as a robust method to achieve a stable performance of the ultrafiltration system at this site. 相似文献
993.
L. L. Hess E. M. L. M. Novo D. M. Slaymaker J. Holt C. Steffen D. M. Valeriano 《International journal of remote sensing》2013,34(7):1527-1555
Four Validation Overflights for Amazon Mosaics (VOAM) aerial video surveys have been carried out in the Brazilian Amazon to provide ground verification for mapping of wetland cover with the Global Rain Forest Mapping (GRFM) Project JERS-1 (Japanese Earth Remote Sensing Satellite) mosaics of the Amazon basin. Surveys in 1995 and 1996, acquired with handheld analog camcorders from small aircraft, were timed to imaging of the GRFM low- and high-water mosaics, and limited to within 600 km of Manaus. For the 1997 and 1999 flights, digital camcorder systems were installed in the Bandeirante survey plane operated by Brazil's National Institute for Space Research. The VOAM97 and VOAM99 surveys circumscribed the Brazilian Amazon, documenting ground conditions at resolutions on the order of 1 m (wide-angle format) and 10 cm (zoom format) for wetlands, forests, savannas, and human-impacted areas. Global Positioning System (GPS) information encoded on the video audio track was extracted by mosaicking software that automatically generates geocoded digital mosaics from video clips. On the 1999 survey, a laser altimeter recorded profiles of terrain and vegetation canopy heights. A validation dataset was compiled from the videography for a portion of the GRFM mosaics extending 6° by 4° in longitude and latitude, using randomly selected points along flight lines. Other applications of the VOAM videography include acquisition of ground control points for image geolocation, creation of a high-resolution geocoded mosaic of a forest study area, forest biomass estimation, and rapid assessment of fire damage. Geocoded digital videography provides a cost-effective means of compiling high-resolution validation datasets for land cover mapping in remote, cloud-covered regions. 相似文献
994.
995.
A method for simulating predictive control of building systems operation in the early stages of building design is presented. The method uses building simulation based on weather forecasts to predict whether there is a future heating or cooling requirement. This information enables the thermal control systems of the building to respond proactively to keep the operational temperature within the thermal comfort range with the minimum use of energy. The method is implemented in an existing building simulation tool designed to inform decisions in the early stages of building design through parametric analysis. This enables building designers to predict the performance of the method and include it as a part of the solution space. The method furthermore facilitates the task of configuring appropriate building systems control schemes in the tool, and it eliminates time consuming manual reconfiguration when making parametric analysis. A test case featuring an office located in Copenhagen, Denmark, indicates that the method has a potential to save energy and improve thermal comfort compared to more conventional systems control. Further investigations of this potential and the general performance of the method are, however, needed before implementing it in a real building design. 相似文献
996.
997.
998.
999.
Steffen Wietzke Marco Reuter Nikolaus Nestle Evgueni Klimov Uri Zadok Bernd M. Fischer Martin Koch 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(7):952-959
We have measured the frequency-dependent dielectric function of semi-crystalline polybutylene terephthalate (PBT) in the terahertz
region between 100 GHz and approximately 2.8 THz. A characteristic band is observed around 2.38 THz. The intensity of this
band is a good indicator of the degree of crystallinity of the different samples. A potential assignment of this band is proposed,
based on the comparison with spectroscopic data of the structurally very similar polyethylene terephtalate (PET). Furthermore,
the frequency-dependent index of refraction of PBT reveals more insight about the morphology and different thermal history
of the samples under investigation. 相似文献
1000.
Christian Rohrdantz Steffen Koch Charles Jochim Gerhard Heyer Gerik Scheuermann Thomas Ertl Hinrich Schütze Daniel A. Keim 《Informatik-Spektrum》2010,36(2):601-611
Methoden und Techniken zur automatischen Verarbeitung und inhaltlichen Erfassung gro?er Mengen an Textdokumenten haben in
den vergangenen Jahren enorm an Bedeutung gewonnen. W?hrend einerseits die Verfügbarkeit und der Zugang zu digitalisierten
Textdokumenten bis dato in ungeahntem Ma?e gestiegen sind, erweist sich die Erfassung des semantischen Inhalts solcher Dokumentsammlungen
als problematisch. Dem expandierenden Forschungsfeld der visuellen Textanalyse und Textvisualisierung kommt dabei eine Schlüsselrolle
bei der L?sung von Problemstellungen aus der Praxis zu. Anhand aktueller Anwendungsbeispiele und einem überblick über den
Stand der Forschung erl?utert dieser Artikel die vielf?ltigen M?glichkeiten, die sich durch visuelle Textanalyse ergeben. 相似文献