全文获取类型
收费全文 | 485篇 |
免费 | 35篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 160篇 |
金属工艺 | 8篇 |
机械仪表 | 15篇 |
建筑科学 | 8篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 105篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 10篇 |
一般工业技术 | 80篇 |
冶金工业 | 66篇 |
原子能技术 | 1篇 |
自动化技术 | 33篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 30篇 |
2021年 | 22篇 |
2020年 | 22篇 |
2019年 | 16篇 |
2018年 | 22篇 |
2017年 | 16篇 |
2016年 | 22篇 |
2015年 | 11篇 |
2014年 | 21篇 |
2013年 | 41篇 |
2012年 | 26篇 |
2011年 | 24篇 |
2010年 | 13篇 |
2009年 | 29篇 |
2008年 | 29篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 17篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 27篇 |
1997年 | 15篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1988年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有520条查询结果,搜索用时 15 毫秒
51.
V Montserrat Orri E López Bonet F Pérez Bueno M Ordis Dalmau N Torrent Quer 《Canadian Metallurgical Quarterly》1997,50(7):798-799
OBJECTIVE: To report an additional case of collecting duct carcinoma of the kidney, known as carcinoma of Bellini. METHODS/RESULTS: A 65-year-old male patient was admitted for left renal pain. An ultrasound scan showed a solid right renal mass. The patient underwent extended radical nephrectomy. Pathological analysis of the surgical specimen disclosed carcinoma of Bellini. The patient is asymptomatic 18 months postoperatively. CONCLUSIONS: Carcinoma of Bellini is an uncommon tumor type arising from the collecting duct cells and accounts for 0.5%-2% of all renal tumors. 相似文献
52.
In this paper the results of the application of a model for the technical and economic sizing of the various components that make up medium sized wind-powered pumped hydrostorage systems are discussed. The characteristics and unit energy cost of each technically feasible combination of components are determined by applying the model in the island of El Hierro (Canarian archipelago). This enables the selection of the most viable composition for the system from an economic point of view given certain technical restrictions. The results of the application of the model (developed in Part I) in El Hierro indicate that an annual renewable energy penetration of 68.40% can be achieved. This would mean a diesel oil saving of 7364 m3 and a decrease in CO2 emissions of 20.91 Gg. Furthermore, the system would be economically competitive with conventional systems if fuel prices were 0.283 €/l. 相似文献
53.
Priscila M. P. Souza Diego Carballares Luciana R. B. Gonalves Roberto Fernandez-Lafuente Sueli Rodrigues 《International journal of molecular sciences》2022,23(22)
Lipase B from Candida antarctica was immobilized on heterofunctional support octyl agarose activated with vinyl sulfone to prevent enzyme release under drastic conditions. Covalent attachment was established, but the blocking step using hexylamine, ethylenediamine or the amino acids glycine (Gly) and aspartic acid (Asp) altered the results. The activities were lower than those observed using the octyl biocatalyst, except when using ethylenediamine as blocking reagent and p-nitrophenol butyrate (pNPB) as substrate. The enzyme stability increased using these new biocatalysts at pH 7 and 9 using all blocking agents (much more significantly at pH 9), while it decreased at pH 5 except when using Gly as blocking agent. The stress inactivation of the biocatalysts decreased the enzyme activity versus three different substrates (pNPB, S-methyl mandelate and triacetin) in a relatively similar fashion. The tryptophane (Trp) fluorescence spectra were different for the biocatalysts, suggesting different enzyme conformations. However, the fluorescence spectra changes during the inactivation were not too different except for the biocatalyst blocked with Asp, suggesting that, except for this biocatalyst, the inactivation pathways may not be so different. 相似文献
54.
W. C. Amaral L. V. R. Arruda S. S. Bueno A. S. Barbara M. A. Silva H. J. Almeida Jr. M. C. Castanho 《Journal of Process Control》1992,2(3)
A CAD system for off-line industrial process identification is presented. The system has two modules. In the first data acquisition is performed. The second performs the process identification procedure. The functions and facilities of these methods are described, which include: the configuration of the data acquisition procedure to be performed, preliminary data analysis, model structure and parameter estimation method selection, time varying parameter estimation and model validation. An industrial application in petrochemical process identification is presented. 相似文献
55.
56.
57.
Traina C Traina AJ Araújo MR Bueno JM Chino FJ Razente H Azevedo-Marques PM 《Computer methods and programs in biomedicine》2005,80(Z1):S71-S83
This paper presents a new Picture Archiving and Communication System (PACS), called cbPACS, which has content-based image retrieval capabilities. The cbPACS answers range and k-nearest- neighbor similarity queries, employing a relational database manager extended to support images. The images are compared through their features, which are extracted by an image-processing module and stored in the extended relational database. The database extensions were developed aiming at efficiently answering similarity queries by taking advantage of specialized indexing methods. The main concept supporting the extensions is the definition, inside the relational manager, of distance functions based on features extracted from the images. An extension to the SQL language enables the construction of an interpreter that intercepts the extended commands and translates them to standard SQL, allowing any relational database server to be used. By now, the system implemented works on features based on color distribution of the images through normalized histograms as well as metric histograms. Metric histograms are invariant regarding scale, translation and rotation of images and also to brightness transformations. The cbPACS is prepared to integrate new image features, based on texture and shape of the main objects in the image. 相似文献
58.
Especially in warm climates, a considerable fraction of the electricity demand in commercial buildings is due to the intensive use of air-conditioning systems. Airport buildings in sunny and warm regions present a perfect match between energy demand and solar resource availability. Airport buildings are also typically large and horizontal, isolated and free of shading, and have a great potential for the integration of solar photovoltaic (PV) systems. In this work, we assess the potential impact in energy demand reduction at the Florianopolis International Airport in Brazil (27°S, 48°W) with the use of building-integrated photovoltaic (BIPV) systems. We analyse the building’s hourly energy consumption and solar irradiation data, to assess the match between energy demand and potential generation, and we estimate the PV power necessary to supply both the total amount and fractions of the annual energy demand. Our results show that the integration of PV systems on airport buildings in warm climates can supply the entire electric power consumption of an airport complex, in line with the general concept of a zero-energy building (ZEB). 相似文献
59.
V.P. de Souza D. Costa D. dos Santos A.G. Sato J.M.C. Bueno 《International Journal of Hydrogen Energy》2012
The effect of Pt addition on the oxi-reduction properties of α-Al2O3-supported Ni catalysts, with different degrees of interaction between NiO and the α-Al2O3 support, was studied using atmospheres of H2, H2/H2O, and CH4/H2O. The effect of Pt promotion on the reduction of NiO with H2 was significant for NiO species that interacted more strongly with the alumina surface, but was much lower when a NiAl2O4-like bulk phase was formed. For samples activated with H2, although metal dispersion decreased with increasing Pt content, the activity was maintained constant by the presence of Pt sites. For samples activated with a CH4/H2O mixture, the activity increased with increasing Pt content, due to the higher reducibility of Ni in the Pt-promoted catalysts. The Pt promotion effect was stable; there was no important decrease in the influence of Pt on NiO reduction, even after high temperature re-oxidation of the catalysts. 相似文献
60.
Ieda Rottava Priscila Fernanda Cortina Camila Elis Grando Helen Treichel Altemir J. Mossi Rogério L. Cansian Enrique G. Oestreicher 《LWT》2010,43(7):1128-1131
This work is focused on the bioconversion of (−)β-pinene and R-(+)-limonene to α-terpineol. To carry out the present study, 400 microorganisms were tested for their ability to bioconvert the substrates. From the microorganisms, no one was able to convert R-(+)-limonene and 4 were able to bioconvert (−)-β-pinene to oxygenated monoterpenes. The metabolites recovered were α-terpineol (2856.54 ± 50.23 mg/L) and fenchol (traces) for Aspergillus niger ATCC 16404, α-terpineol (688.13 ± 41.27 mg/L) for A. niger ATCC 9642, α-terpineol (172.07 ± 32.94 mg/L) for A. niger ATCC 1004 and α-terpineol (24.38 ± 2.78 mg/L) and trans-pinocarveol (traces) for Penicillium camembertii ATCC 4845. After screening and optimization experiments, the best experimental condition for bioconversion of (−)β-pinene to α-terpineol was established using A. niger ATCC 16404 at 35 °C without addition of vitamin solution, yielding a conversion in α-terpineol of 15494.34 ± 193.87 mg/L. 相似文献