全文获取类型
收费全文 | 1940篇 |
免费 | 122篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 11篇 |
综合类 | 2篇 |
化学工业 | 835篇 |
金属工艺 | 36篇 |
机械仪表 | 21篇 |
建筑科学 | 55篇 |
矿业工程 | 7篇 |
能源动力 | 39篇 |
轻工业 | 323篇 |
水利工程 | 9篇 |
石油天然气 | 10篇 |
无线电 | 72篇 |
一般工业技术 | 324篇 |
冶金工业 | 101篇 |
原子能技术 | 2篇 |
自动化技术 | 218篇 |
出版年
2024年 | 6篇 |
2023年 | 40篇 |
2022年 | 201篇 |
2021年 | 194篇 |
2020年 | 56篇 |
2019年 | 62篇 |
2018年 | 80篇 |
2017年 | 63篇 |
2016年 | 73篇 |
2015年 | 60篇 |
2014年 | 88篇 |
2013年 | 146篇 |
2012年 | 98篇 |
2011年 | 127篇 |
2010年 | 97篇 |
2009年 | 97篇 |
2008年 | 110篇 |
2007年 | 59篇 |
2006年 | 70篇 |
2005年 | 59篇 |
2004年 | 50篇 |
2003年 | 30篇 |
2002年 | 40篇 |
2001年 | 18篇 |
2000年 | 16篇 |
1999年 | 13篇 |
1998年 | 22篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
1911年 | 2篇 |
排序方式: 共有2065条查询结果,搜索用时 15 毫秒
71.
Vladimir Klochkov Nataliya Kavok Ganna Grygorova Olga Sedyh Yuri Malyukin 《Materials science & engineering. C, Materials for biological applications》2013,33(5):2708-2712
In this paper the process of nonfunctionalized negatively charged orthovanadate nanoparticle accumulation and redistribution in cells dependent on their shape and size was investigated. Aqueous colloidal solutions of nReVO4:Eu3 + (Re = Gd, Y, La) luminescent nanocrystals of different sizes and shapes have been synthesized. The average sizes of spherical particles were 2, 20, and 300 nm, of spindle-like particles – 22 × 6.3 nm, and of rod-like particles – 57 × 4.4 nm. Luminescence of nReVO4:Eu3 + nanocrystals was effectively excited by UV and visible irradiation. By means of luminescence microscopy and luminescence microspectroscopy, it has been revealed that spherical nanocrystals with an average diameter of 2 nm tend to accumulate mainly in the rat hepatocyte nuclei in situ and also in the isolated nuclei of these cells. An additional experiment has shown that nanoparticles reveal tropism to nuclear structural components. The penetration into nuclei does not require any modifications of the surface of nanoparticle and is governed by the shape and size of nanoparticle and also is determined by the cellular type. 相似文献
72.
Omar Arafat Kdudsi Khalil Olga Maria Mascarenhas de Faria Oliveira José Carlos Rebuglio Vellosa Andreza Urba de Quadros Loriangela Marceli Dalposso Thaysa Ksiaskiewcz Karam Rubiana Mara Mainardes Najeh Maissar Khalil 《Food chemistry》2012
The objective of this study was to evaluate the antifungal and antioxidant activities of curcumin, ascorbic acid and the mixture of these two compounds. For the antifungal assay, the minimum inhibitory concentrations (MIC) were determined using Candida strains (ATCC and clinical isolates). Curcumin alone inhibited growth of Candida albicans yeast cells, whereas ascorbic acid did not present effects. However, when the mixture of ascorbic acid and curcumin was assayed to determine the association of the two compounds, the curcumin MIC decreased 5- to 10-fold. In the antioxidant assays, the sum of the alone activities of curcumin and ascorbic acid were lower than the activity of the two-compound mixture. This study highlights the importance of the association between two common antioxidants in foods, to improve the antifungal and antioxidant activities of curcumin (in vitro), and can be applied to Candida spp. infection and diseases associated with oxidative stress. 相似文献
73.
José L. Rodríguez Rosanna M. Minardi Erica P. Schulz Olga Pieroni Pablo C. Schulz 《Journal of surfactants and detergents》2012,15(2):147-155
The composition of the mixed micelles formed by benzethonium chloride and dodecyl trimethyl ammonium bromide in water were
experimentally determined by a combination of surfactant ion-selective electrodes and UV–Vis spectroscopy measurements. Results
were compared with the computed compositions from three theories on mixed micelles available in the literature (Regular Solution,
Motomura’ and Georgiev’s). The basis of the Junquera and Aicart method and the determination of the micelle aggregation number
(N) by pyrene fluorescence quenching, i.e., the constancy of N and the mixed micelle composition when the total concentration is changed, were not supported by our experimental results. Experimental micelle compositions were statistically equal to those computed
by Regular Solution Theory. The mixed micelle composition and the quantity of non-micellized surfactant molecules change with
concentration above the critical micelle concentration, and therefore do not support the assumptions used in the Junquera
and Aicart procedure and in the determination of N by pyrene fluorescence quenching. The reason why the latter procedure gives N values similar to those obtained from other techniques is discussed. 相似文献
74.
Jonathan Mosqueda-Melgar Rosa M. Raybaudi-Massilia Olga Martín-Belloso 《Food and Bioproducts Processing》2012,90(2):205-214
The effect of combining high-intensity pulsed electric fields (HIPEF) with citric acid or cinnamon bark oil, as antimicrobial substances, on the microbiological shelf life of strawberry, orange, apple, pear and tomato juices was evaluated in addition to the sensory properties of these products. An extension of the microbiological shelf life of fruit juices treated by HIPEF with or without antimicrobial substances was observed in comparison with those juices without processing. Naturally occurring microorganisms in the juices were inactivated by HIPEF treatment. Among the HIPEF treated juices, those from strawberry and orange did not show microbial growth along the 91 days of storage at 5 °C. However, resident microbial populations in apple, pear and tomato juices only were controlled during that time when HIPEF was combined with antimicrobials. Therefore, combinations of those treatments may be a feasible alternative to thermal pasteurization to ensure the microbiological quality and safety in juices, and to avoid the risk of foodborne illness caused by the consumption of these commodities. No significant changes on the sensory attributes in all studied fruit juices processed by HIPEF were found; but, when citric acid or cinnamon bark oil were added, noticeable changes on some sensory attributes such as aroma, taste and sourness of these fruit juices were perceived. 相似文献
75.
Die im Art. 17 der Datenschutz-Grundverordnung (DSGVO) enthaltene Regelungen für das Löschen, insbesondere die Pflicht, Dritte über die Löschanfragen zu informieren, sind mit einem hohen Aufwand für die Verantwortlichen verbunden, sodaßs sie ohne eine technische Unterstützung in der Praxis nicht umgesetzt werden können. Die zurzeit jedoch fehlenden technischen Lösungen führen zu einer Lücke zwischen den Rechtsvorschriften und den derzeitigen technischen Möglichkeiten, während die DSGVO ab Mai 2018 anzuwenden ist. Um diese Lücke zu schließen, wird im Folgenden zunächst analysiert, welche Möglichkeiten im Allgemeinen bestehen, das Löschen im Internet gemäß Art. 17 technisch umzusetzen. Anschließend wird eine Lösung für die Verteilung der Löschanfragen an die Verantwortlichen vorgestellt, das auf der Kombination der Technik mit dem Gesetz beruht und sowohl den Betroffenen als auch den Verantwortlichen ein Werkzeug zur Unterstützung des Art. 17 zur Verfügung stellt. 相似文献
76.
77.
78.
Olga Escuredo Luís R. Silva Patrícia Valentão María C. Seijo Paula B. Andrade 《Food chemistry》2012,130(3):671-678
Twenty-three honey samples from Galicia (Northwest Spain) were analysed to determine their botanical origin, phenolic compounds and antibacterial activity. In all samples Rubus pollen was predominant, followed by that of Castanea sativa. Other important pollens found belong to Cytisus type, Trifolium repens, Echium, Eucalyptus globulus, Erica umbellata, Erica cinerea, Campanula type and Frangula alnus.Eight phenolic compounds (caffeic, p-coumaric and ellagic acids, pinocembrin, chrysin, galangin, tectochrysin and kaempferol) were determined by solid-phase extraction (SPE) followed by HPLC/DAD analysis. p-Coumaric and ellagic acids were the main constituents of the phenolic fraction (ca. 5.5 mg/kg each, mean value), followed by the pair chrysin plus galangin (ca. 1.2 mg/kg, mean value) and pinocembrin (ca. 1.0 mg/kg, mean value). Antibacterial activity was checked against five Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and four Gram-negative bacteria (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium). B. cereus and P. mirabilis were the most sensitive microorganisms. This is the first study concerning the phenolic compounds and antibacterial activity of Rubus honey, which proved to be a good source of phenolic compounds and antimicrobial agents with potential health benefits. 相似文献
79.
80.