全文获取类型
收费全文 | 384篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 95篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 13篇 |
能源动力 | 13篇 |
轻工业 | 47篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 80篇 |
冶金工业 | 6篇 |
原子能技术 | 3篇 |
自动化技术 | 107篇 |
出版年
2023年 | 9篇 |
2022年 | 11篇 |
2021年 | 17篇 |
2020年 | 9篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 33篇 |
2012年 | 17篇 |
2011年 | 40篇 |
2010年 | 21篇 |
2009年 | 19篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有404条查询结果,搜索用时 15 毫秒
51.
José Alfredo Tirado-Méndez Flavio Iturbide-Sánchez Oleg Golovin Hildeberto Jardón-Aguilar 《国际射频与微波计算机辅助工程杂志》2004,14(2):144-152
In this article, four linearizing techniques are compared with each other when they are used in a common-emitter SiGe HBT LNA. Finally, when all of them are employed together, improved linearity of the LNA is observed and more than 10 dBm of IIP3 and −5 dBm of 1-dB gain input compression point are realized when the circuit is fed with 2.4 V. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 144–152, 2004. 相似文献
52.
53.
Memory occupation of geographic data and efficiency of the selection and elaboration algorithms are challenging problems in designing a system for polygonal data processing. They arise basically from the large number of polygon vertices necessary to properly approximate territory maps. Since the number of vertices is determined by the expected resolution, data compression can only be achieved by reducing the memory occupation of each point. On the other hand, more efficient algorithms are obtained if unnecessary operations are carefully avoided: in geographic data processing this is done by precisely delimiting the territory areas to be processed. In this paper, the SECT coding technique is presented, which meets both the above requirements. Its data compression capability is proved with reference to points, lines and regions coding, having considered geographic data of different density. Furthermore, the benefits it ensures in terms of both CPU time and I/O operation savings are discussed. 相似文献
54.
Antonio Raffo Irene Baiamonte Nicoletta Nardo Flavio Paoletti 《European Food Research and Technology》2007,225(3-4):395-405
Physical (weight, firmness) and compositional (sugars, organic acids, ascorbic acid, phenolic compounds and carotenoids) changes
of red sweet peppers (Capsicum annuum L.) were monitored during 21 days of cold storage (at 7.5 °C); fruits were stored without packaging, packaged in low density
polyethylene bags, or after hot water dipping (53 °C for 4 min) and packaging. Packaging prevented water loss, and preserved
the firmness of the fresh product. Sugars (fructose and glucose) content was practically constant throughout the whole storage
time, for all treatments. A moderate accumulation of citric acid was observed during storage, but no marked effects of packaging
and hot water dipping on citric and malic acid content. Ascorbic acid content slightly increased in unpackaged and packaged
fruits, but not in treated+packaged peppers. Hydroxycinnamics total content seemed not to be affected by cold storage, packaging
or hot water treatment, whereas glycosylated flavonoids showed somewhat lowered levels during storage, particularly in the
case of unpackaged and packaged+treated fruits. Regarding carotenoids content, the effect of the considered storage conditions
seemed to be much smaller than that due to ripening stage. Provitamin A content showed an increasing trend in unpackaged and
packaged fruits; packaged+treated peppers were characterised by a lower retention of provitamin A and a higher level of capsanthin
and cucurbitaxanthin A with respect to not treated fruits. On the whole, packaging and hot water treatment did not produce
noticeable adverse effects on the majority of the examined compositional quality parameters. 相似文献
55.
Effect of the use of anti‐hail nets on codling moth (Cydia pomonella) and organoleptic quality of apple (cv. Braeburn) grown in Alto Adige Region (northern Italy) 下载免费PDF全文
56.
Flavio Della Foglia Gian Luca Chiarello Maria Vittoria Dozzi Paolo Piseri Luca Giacomo Bettini Simone Vinati Caterina Ducati Paolo Milani Elena Selli 《International Journal of Hydrogen Energy》2014
Photoactive membranes coated with TiO2 and Pt/TiO2 nanostructured thin films were produced by one-step deposition of gas phase nanoparticles on glass fiber filters. Pt/TiO2 nanoparticles (0–1.5 wt.% Pt content) were produced by flame spray pyrolysis, starting from liquid solutions of the Ti and Pt precursors, and then expanded in a supersonic beam to be deposited on the filters. The nanostructured coatings were composed of crystalline nanoparticles (mainly anatase phase), without any need of post-deposition annealing. The so obtained photocatalytic membranes were tested in hydrogen production by photo-steam reforming of ethanol in an expressly set-up diffusive photoreactor. The reaction rate was found to increase with increasing the Pt content in the photoactive material, up to 1.5 wt.% Pt. The use of these membranes allowed a significant increase of the hydrogen production rate compared to that obtained with the same photoactive Pt/TiO2 films deposited on a quartz substrate. 相似文献
57.
58.
Federico Pallottino Paolo Menesatti Corrado Costa Graziella Paglia Flavio R. De Salvador Daniele Lolletti 《Food and Bioprocess Technology》2010,3(1):155-159
According to FAO statistics, in 2000, Italy was the second largest hazelnut (Corylus avellana, L. 1753) producer in the world. The price of the stock depends on the nut quality (kernel/nut ratio, nut and seed defect, percentage of peeling, and taste panel scores). The evaluation of peeling efficiency after toasting is generally conducted by trained operators in sight on 100 kernels. This work tests two alternative objective methods of after toasting peeling evaluation based on image analysis. Eleven hazelnut cultivars were analyzed and results were compared with the ones assessed by trained operators. Images were analyzed with two statistical approaches: fixed values of RGB thresholding and trained K Nearest Neighbors (KNN). Root mean squared error (RMSE), estimating the comparison between operators and the two image analysis-based techniques, shows better results for KNN (6.6) with respect to fixed threshold (15.9). 相似文献
59.
The intracellular silver accumulation ({Ag}(in)) upon exposure to carbonate coated silver nanoparticles (AgNP, 0.5-10 μM, average diameter 29 nm) and silver nitrate (20-500 nM) was examined in the wild type and in the cell wall free mutant of the green alga Chlamydomonas reinhardtii at pH 7.5. The {Ag}(in) was measured over time up to 1 h after a wash procedure to remove silver ions (Ag(+)) and AgNP from the algal cell surface. The {Ag}(in) increased with increasing exposure time and with increasing AgNP and AgNO(3) concentrations in the exposure media, reaching steady-state concentrations between 10(-5) and 10(-3) mol L(cell)(-1). According to estimated kinetic parameters, high Ag(+) bioconcentration factors were calculated (>10(3) L L(cell)(-1)). Higher accumulation rate constants were assessed in the cell wall free mutant, indicating a protective role of the cell wall in limiting Ag(+) uptake. The bioavailability of AgNP was calculated to be low in both strains relative to Ag(+), suggesting that AgNP internalization across the cell membrane was limited. 相似文献
60.
Antonio?RaffoEmail author Flavio?Paoletti Marco?Antonelli 《European Food Research and Technology》2004,219(4):360-368
Soluble solid, sugar, organic acid, flavonol and carotenoid content were determined in seabuckthorn berries of the three German cultivars Askola, Hergo and Leikora, collected at different harvesting times, to provide a more thorough knowledge of quality changes occurring during ripening of the berries. The main organic acids were malic (1940–4660 mg/100 g), quinic (810–2820 mg/100 g), ascorbic (180–370 mg/100 g) and citric acid (90–160 mg/100 g). In all three cultivars a marked decline in total organic acid concentration was observed during ripening. The pattern of variation of sugars, glucose (0.26–2.10 g/100 g) and fructose (0.14–0.54 g/100 g), was somewhat different among the three cultivars. In all three cultivars ascorbic acid concentration decreased during ripening. The main flavonols were isorhamnetin (350–660 mg/kg), quercetin (30–100 mg/kg) and kaempferol (2–5 mg/kg). The trends of flavonol content during ripening were quite different among the three cultivars. The main carotenoids were zeaxanthin (30–150 mg/kg), -carotene (3–50 mg/kg) and -criptoxanthin (5–19 mg/kg). The genotype seemed to affect both the extent of carotenoid accumulation and the carotenoid profile but in all three cultivars ripening was accompanied by an increase in total carotenoid concentration. The various classes of antioxidants showed quite different patterns of variation during ripening, achieving their maximum level at different harvesting dates. 相似文献