全文获取类型
收费全文 | 517篇 |
免费 | 13篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 108篇 |
金属工艺 | 11篇 |
机械仪表 | 10篇 |
建筑科学 | 12篇 |
矿业工程 | 1篇 |
能源动力 | 17篇 |
轻工业 | 44篇 |
水利工程 | 1篇 |
无线电 | 72篇 |
一般工业技术 | 97篇 |
冶金工业 | 49篇 |
原子能技术 | 8篇 |
自动化技术 | 92篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 23篇 |
2013年 | 32篇 |
2012年 | 32篇 |
2011年 | 35篇 |
2010年 | 24篇 |
2009年 | 31篇 |
2008年 | 37篇 |
2007年 | 26篇 |
2006年 | 19篇 |
2005年 | 13篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 28篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有530条查询结果,搜索用时 20 毫秒
31.
Helmi Keskinen Jyrki M. Mäkelä Mikko Aromaa Jorma Keskinen Sami Areva Cilâine V. Teixeira Jarl B. Rosenholm Viljami Pore Mikko Ritala Markku Leskelä Mari Raulio Mirja S. Salkinoja-Salonen Erkki Levänen Tapio Mäntylä 《Catalysis Letters》2006,111(3-4):127-132
Titania and titania-silver nanoparticle deposits were made by Liquid Flame Spray technique, in which the liquid precursor
is injected into a high temperature flame, where it will evaporate and nucleate to nanosize particles. One-step and two-step
methods were used for preparation of titania-silver deposits. The amount of silver added was 1 wt%. The deposits were collected
in the flame zone on steel and glass surfaces and were analyzed by TEM, EDS, XPS and SAXS. The titania deposits consisted
of porous nanosized titania agglomerates of primary particles (~10 nm). With silver addition, small spherical silver metal
particles (~2 nm) were detected on the agglomerates. An increase in the photocatalytic activity was verified by stearic acid
decomposition and biofilm removal using Deinococcus geothermalis as the model organism. 相似文献
32.
Maarit J. Rein Velimatti Ollilainen Mikko Vahermo Jari Yli-Kauhaluoma Marina Heinonen 《European Food Research and Technology》2005,220(3-4):239-244
In most fruit and berry products the attractive red color is unstable and easily susceptible to degradation. The colors of strawberry and raspberry juices can be enhanced and stabilized by the addition of cinnamic acids. The aim of this study was to identify the novel anthocyanin products responsible for the improved juice color. The pyranoanthocyanins formed were detected using high-performance liquid chromatography, and the fractions from this were analyzed using a nano-ESI tandem MS technique. The pyranoanthocyanins identified were formed from reactions of the main anthocyanins of strawberry and raspberry juices with ferulic acid or sinapic acid. The new anthocyanin derivatives were the 4-vinylguaiacol and 4-vinylsyringol adducts of pelargonidin and cyanidin. This is the first time that pelargonidin 3-glucoside-based vinylphenol pyranoanthocyanins and pyranoanthocyanins with more complex sugar residues have been found. This is also the first time pyranoanthocyanins have been detected in strawberry and raspberry juices. 相似文献
33.
Moldavian balm (Dracocephalum moldavica L., Lamiaceae) is a perennial herb native to central Asia and naturalized in eastern and central Europe. It is commonly consumed as a food-related product and as a herbal preparation because of its reputed medicinal properties. Despite its importance, few reports exist in the literature regarding the chemistry or antioxidant activity of this species. In this study, the aerial material of Moldavian balm collected from Iran was extracted by Soxhlet using seven solvents of different polarity, viz., petroleum ether, dichloromethane, acetonitrile, ethyl acetate, methanol, n-butanol and water. The qualitative-quantitative chemical composition of each extract was determined using high-performance liquid chromatography coupled to photodiode array detection. For each extract, the total phenolic content was estimated as was the in vitro antioxidant activity using the iron(III) reduction assay, the β-carotene-linoleic acid bleaching assay and the 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) free radical scavenging assays. Hydroxylated cinnamic acids, their derivatives and flavonoids were identified and quantified within the extracts, with rosmarinic acid being the most abundant component identified. The extracts demonstrated different degrees of potency within each assay, however, the observed pattern was not necessarily replicated between assays indicating the importance of the use of more than one screening technique to estimate the antioxidant activity of plant extracts. 相似文献
34.
Jaakko Marttila Markus All��n Mikko Valkama 《Circuits, Systems, and Signal Processing》2011,30(4):775-797
This article discusses the applicability of quadrature ΣΔ modulator (QΣΔM) based analog-to-digital (A/D) conversion in cognitive
radio (CR) receivers. First, unavoidable in-phase/quadrature (I/Q) mismatch effects, limiting the dynamic range, are analyzed
in closed-form in the case of a first-order modulator. In addition, using the derived analytical converter model, it is shown
that notching the signal transfer function (STF) of the modulator at the mirror frequencies of the desired signals will effectively
cancel the I/Q imbalance induced mirror-frequency interference in case of the modulator feedback mismatch. In practice, such
STF design is easy to implement within the existing converter circuitry, as will be demonstrated in this article. The latter
part of the article proposes a novel complex multiband QΣΔM scheme, particularly aimed for the CR receivers. This multiband
scheme allows parallel reception of scattered frequency chunks in the CR context and is stemming from the additional degrees
of freedom in noise transfer function (NTF) design, provided by the QΣΔM principle. Here multiple noise shaping notches on
distinct frequencies are effectively realized through proper design of complex NTF. The modulator structure also allows flexible
reconfigurability of the notches with straightforward parameterization of the modulator transfer functions. When combined
with the above mirror-frequency rejecting STF design, the concept is demonstrated and proved effective and robust against
I/Q imbalances using practical radio signal simulations in realistic received signal conditions. 相似文献
35.
建筑通常被认为是老年人的艺术范畴,或者,年轻建筑师和女建筑师做的概念和模型。年龄是影响这一判断的标准。对于20岁的年轻人而言.40岁的人就已经是老朽了。或者从另一个角度来看,建筑师Kristian Gullichsen和Juhani Pallasmaa在20世纪70年代被《赫尔辛基消息报》报导的时候被称为青年建筑师,尽管那时他们已经40多岁了。 相似文献
36.
Vincenzo Di Marzo Mikko Griinari Gianfranca Carta Elisabetta Murru Alessia Ligresti Lina Cordeddu Elena Giordano Tiziana Bisogno Maria Collu Barbara Batetta Sabrina Uda Kjetil Berge Sebastiano Banni 《International Dairy Journal》2010,20(4):231-235
Evidence suggests that dietary long chain polyunsaturated fatty acids (LCPUFAs), and particularly those belonging to the n-3 family, may influence the brain fatty acid profile and, thereby, the biosynthesis of endocannabinoids in rodents. However, the doses used are usually quite high and not comparable with human intake. Recently, we have shown that relatively low doses of dietary n-3 LCPUFAs (4 weeks), in the form of either fish or krill oil, balanced for EPA and DHA content, and against a control diet with no EPA and DHA and similar contents of oleic, linoleic and α-linolenic acids, lower the concentrations of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), in the visceral adipose tissue, and of AEA in the liver and heart, of obese Zucker rats. This, in turn, is associated with lower levels of arachidonic acid in membrane phospholipids and with amelioration of some metabolic syndrome parameters. We investigated here whether in Zucker rats, under the same conditions, fish and krill oil are also able to influence LCPUFA and endocannabinoid profiles in brain. Only krill oil was able to increase significantly DHA levels in brain phospholipids, with no changes in arachidonic acid. DHA increase was associated with lower levels of 2-AG in the brain, whereas AEA and its congeners, N-palmitoylethanolamine and N-oleoylethanolamine, were unchanged. We conclude that, despite the strong impact of dietary n-3 fatty acid on endocannabinoid levels previously observed in peripheral tissues, in the brain only 2-AG is affected by dietary krill oil, suggesting that the beneficial effect of the latter on the metabolic syndrome is mostly exerted by modifying peripheral endocannabinoids. Nevertheless, possible effects of dietary krill oil in the brain through modification of 2-AG levels deserve further investigation. 相似文献
37.
38.
This paper examines the formation of heating practices at the time of moving house. Interviews on occupant changes in Finnish single-family houses with a focus on heating arrangements and thermal comfort reveal that practice formation in and around occupant changes is a complex process of aligning elements where the house stands out as a coordinative and coordinated aggregate. As houses pass from one set of occupants to the next, they carry practices and delineate new ways of operation to the new occupants. The study demonstrates the temporal unfolding of the hidden complexity to what seems like a straightforward process of residents interacting with a new heating system and home. The findings contribute to the understanding of the domestic sphere as a space for practice formation. 相似文献
39.
There has been a demand for uniform CAD standards in the construction industry ever since the large-scale introduction of computer aided design systems in the late 1980s. While some standards have been widely adopted without much formal effort, other standards have failed to gain support even though considerable resources have been allocated for the purpose. Establishing a standard concerning building information modeling has been one particularly active area of industry development and scientific interest within recent years. In this paper, four different standards are discussed as cases: the IGES and DXF/DWG standards for representing the graphics in 2D drawings, the ISO 13567 standard for the structuring of building information on layers, and the IFC standard for building product models. Based on a literature study combined with two qualitative interview studies with domain experts, a process model is proposed to describe and interpret the contrasting histories of past CAD standardisation processes. 相似文献
40.
Peetu Nieminen Salvador Esque Ali Muhammad Jouni Mattila Jukka Vyrynen Mikko Siuko Matti Vilenius 《Fusion Engineering and Design》2009,84(7-11):1420-1424
Department of Intelligent Hydraulics and Automation (IHA) of Tampere University of Technology has been involved in the European Fusion program since 1994 within the ITER reactor maintenance activities. In this paper we discuss the design and development of a six degrees of freedom water hydraulic manipulator with a force feedback for teleoperation tasks. The manipulator is planned to be delivered to Divertor Test Platform 2 (DTP2) during year 2008. The paper also discusses the possibility to improve the fail safe and redundant operation of the manipulator. During the design of the water hydraulic manipulator, special provisions have been made in order to meet the safety requirements such as servo valve block for redundant operation and safety vane brakes for fail safe operation. 相似文献