全文获取类型
收费全文 | 386篇 |
免费 | 16篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 60篇 |
金属工艺 | 2篇 |
机械仪表 | 4篇 |
建筑科学 | 9篇 |
能源动力 | 16篇 |
轻工业 | 34篇 |
水利工程 | 12篇 |
石油天然气 | 15篇 |
武器工业 | 1篇 |
无线电 | 65篇 |
一般工业技术 | 67篇 |
冶金工业 | 10篇 |
原子能技术 | 4篇 |
自动化技术 | 97篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 23篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 16篇 |
2016年 | 23篇 |
2015年 | 14篇 |
2014年 | 18篇 |
2013年 | 51篇 |
2012年 | 22篇 |
2011年 | 27篇 |
2010年 | 11篇 |
2009年 | 18篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 5篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有406条查询结果,搜索用时 15 毫秒
71.
Study of three‐dimensional natural convection and entropy generation in an inclined solar collector equipped with partitions
下载免费PDF全文
![点击此处可从《亚洲传热研究》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Olfa Yejjer Lioua Kolsi Walid Aich Abdullah A.A.A. Al‐Rashed Mohamed Naceur Borjini Habib Ben Aissia 《亚洲传热研究》2017,46(8):1312-1326
Three‐dimensional natural convection in an inclined solar collector equipped with partitions has been investigated numerically. The presence of partitions improves the performances of the collector by increasing the heat transfer near the absorber. A parametric study was done for various partitions length and Rayleigh numbers, while Prandtl number and inclination angle were fixed at 0.71 and 45°, respectively. Results are reported in terms of isosurfaces of temperature, isotherms, particles trajectories, velocity vector projection, average Nusselt number along the absorber plate and entropies generation contours. 相似文献
72.
Salma Sultan Walid Mottawea JuDong Yeo Riadh Hammami 《International journal of molecular sciences》2021,22(23)
Over the past decade, gut microbiota dysbiosis has been linked to many health disorders; however, the detailed mechanism of this correlation remains unclear. Gut microbiota can communicate with the host through immunological or metabolic signalling. Recently, microbiota-released extracellular vesicles (MEVs) have emerged as significant mediators in the intercellular signalling mechanism that could be an integral part of microbiota-host communications. MEVs are small membrane-bound vesicles that encase a broad spectrum of biologically active compounds (i.e., proteins, mRNA, miRNA, DNA, carbohydrates, and lipids), thus mediating the horizontal transfer of their cargo across intra- and intercellular space. In this study, we provide a comprehensive and in-depth discussion of the biogenesis of microbial-derived EVs, their classification and routes of production, as well as their role in inter-bacterial and inter-kingdom signaling. 相似文献
73.
Walid Bahloul Flavien Mélis Véronique Bounor-Legaré Philippe Cassagnau 《Materials Chemistry and Physics》2012
Polypropylene/titanium dioxide (PP/TiO2) nanocomposites can be prepared using a novel method based on the hydrolysis–condensation reactions (sol–gel method) of titanium alkoxide inorganic precursors that have been premixed with polypropylene under molten conditions. The resultant nanocomposites were characterised by transmission electronic microscopy (TEM), X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). These techniques showed the formation of the titanium oxi-hydroxide chemical structure (TixOy(OH)z) with a diameter of approximately 10 nm in the polymer matrix. Furthermore, a condensation degree of around 17% was determined using XPS analysis. The antibacterial activity was tested according to the JIS Z 2801:2000 standard with Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in the absence of light. Correlations between the microstructure and the chemical composition of PP/TiO2 nanocomposites and the antibacterial properties of these nanocomposites were discussed. The structure of titanium oxi-hydroxide derivative particles (TixOy(OH)z) within the polypropylene matrix has been shown to impact strongly on the antibacterial properties in comparison with the results obtained with a dispersion of anatase titanium dioxide into the PP. 相似文献
74.
Raid A. Ismail Evan T. Salim Walid K. Hamoudi 《Materials science & engineering. C, Materials for biological applications》2013,33(1):47-52
Pulsed laser deposition, under dry and water vapor conditions, was employed to synthesize nanostructured hydroxyapatite films by pulsed laser deposition (PLD) of chlorapatite target for the purpose of coating metallic bone implants by this material. A pulsed Nd:YAG laser operating at a wavelength of 1064 nm and emitting 9 ns pulses was used for deposition. AFM microscopy, FTIR spectroscopy, optical microscopy, adhesion and microhardness measurements were conducted to characterize the films. The in vitro test for the synthesized hydroxyapatite was performed using simulated body fluid (SBF). The results showed a successful transformation of the chlorapatite to hydroxyapatite films characterized by all the HAp peaks with 60 nm root mean square roughness, (80–327) nm grain size, and a microhardness of 512 HV. 相似文献
75.
Whether an industrial organisation is involved with production of new goods or engaged in reverse logistics to recycle used products, the items produced that do not meet specifications can cost the organisation in many different ways. The administrative expenses of handling returned items and the cost of reworking the items that have failed in plant quality control or returned by customers can be of concern to the manufacturers. While these are measurable costs, there are other costs such as loss of customers’ good will which are hard, if not impossible, to estimate. The model presented in this paper is aimed at optimising the measurable cost of reworking/scrapping the off-specification items as well as the cost of adjusting manufacturing processes with the aim of reducing or eliminating rejected pieces. The adjustment of process specification in relation to customer specification is a strategy that can affect production and quality cost. Consideration for optimal production specification is one of the elements of the model presented in this paper. In the proposed model, the direct cost of poor quality has been represented by a symmetrical truncated loss function. We have considered investment to adjust the mean and variance of the process. A numerical example is presented to demonstrate how the model can work in a real-world setting. 相似文献
76.
Marauo Davis Fernando Hung-Low Walid M. Hikal Louisa J. Hope-Weeks 《Journal of Materials Science》2013,48(18):6404-6409
A facile, sol–gel method has afforded highly crystalline, Fe-doped SnO2 nanoarchitectures with efficient photocatalytic degradation of rhodamine B (RhB) under ultraviolet irradiation. The effects of iron modification to tin dioxide were investigated. The structural properties were characterized by powder X-ray diffraction, gas sorption (adsorption/desorption) techniques, scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy (EDS). The photocatalytic activity of these materials was studied by examining the degradation of RhB with pure SnO2 and each Fe modified sample (3 and 5 %), all annealed at 350 °C. Diffraction results reveal that the synthesized nanocrystals are ~3 nm in diameter. Gas sorption analyses detail high-specific surface areas (>330 m2 g?1). Electron microscopy studies illustrate the enhanced porosity brought on through annealing. EDS confirms the presence of Fe in the most active Fe-modified SnO2 sample. It is found that the 5 % Fe-modified SnO2 degrades RhB by more than half after 2 h. 相似文献
77.
Ramona Thalinger Michael Stöger-Pollach Walid Hetaba Michael Feuerbacher Bernhard Klötzer Simon Penner 《Materials Chemistry and Physics》2013
Model systems of the clean and pure oxides Y2O3 and ZrO2, as well as Cu/Cu2O and Ni/NiO particles embedded in the respective oxides have been used to study the reduction behavior of the oxides and the eventually associated metal-support interaction effects in oxide-supported systems. Particular emphasis has also been given to the influence of the phase transformation in ZrO2-containing systems on metal-support interaction. Whereas Y2O3 has been found to be an outstandingly structurally and thermally stable oxide even upon reduction in hydrogen up to 1073 K, ZrO2 was found to undergo a series of phase transformations from amorphous ZrO2 to polycrystalline tetragonal ZrO2 (∼673 K) and subsequently to monoclinic ZrO2 (above 873 K). Both phase transformations were found to be basically dependent on gas partial pressure and annealing rate. However, substantial reduction of the oxides did not take place during the phase transformations. In turn, both Cu- and Ni-containing systems were not observed to be substantially affected by any (strong) metal-support interaction effects such as encapsulation by sub-stoichiometric oxides or reductive formation of intermetallic phases, at least up to temperatures of 1073 K. Equally, for the ZrO2-containing systems, also the phase transformations occurring at elevated temperatures did not cause structural or thermo-chemical alterations of the Cu or Ni-particles. Differences in the metal-support interaction between Cu- and Ni-particles have only been obtained in the structural “reference” systems, that is, if supported on SiO2. Whereas Cu/Cu2O particles on SiO2 are basically unaffected by the reductive treatment at elevated temperatures, a Ni3Si2 intermetallic phase is formed if SiO2-supported Ni/NiO particles are treated in hydrogen at 673 K and above. 相似文献
78.
Inès Thabti Walid Elfalleh Hédia Hannachi Ali Ferchichi Maria Da Graça Campos 《Journal of Functional Foods》2012,4(1):367-374
The total polyphenol and flavonoids in leaves of Morus alba var. alba, Morus alba var. rosa and Morus rubra were determined and identification of their components was carried out. The total content of phenolics varied between 345.20 and 631.53 mg gallic acid equivalents (GAE)/100 g dry weight (DW) basis. The total amount of flavonoids ranged between 193.87 and 398.33 mg rutin equivalents (RE)/100 g DW. Thirteen compounds were isolated by chromatography, and their structures determined to be mainly flavonol glycosides and phenolic acids. Three novel components were identified as kaempferol-7-O-glucoside, quercetin-3-O-β-glucoside-7-O-α-rhamnoside and quercetin-3-O-rhamnoside-7-O-glucoside, for the first time from mulberry leaves. Others known compounds were also identified. 相似文献
79.
Evaluation of Antioxidant Compounds and Total Sugar Content in a Nectarine [Prunus persica (L.) Batsch] Progeny 总被引:1,自引:0,他引:1
Abidi W Jiménez S Moreno MÁ Gogorcena Y 《International journal of molecular sciences》2011,12(10):6919-6935
Epidemiological studies suggest that consumption of fruit rich in phenolic compounds is associated with health-protective effects due to their antioxidant properties. For these reasons quality evaluation has become an important issue in fruit industry and in breeding programs. Phytochemical traits such as total phenolics, flavonoids, anthocyanins, L-ascorbic acid, sugar content and relative antioxidant capacity (RAC) were analyzed over four years in flesh fruit of an F1 population "Venus" × "Big Top" nectarines. Other traits such as harvesting date, yield, fruit weight, firmness, soluble solids concentration (SSC), pH, titratable acidity (TA) and ripening index (RI) were also determined in the progeny. Results showed high variability among genotypes for all analyzed traits. Total phenolics and flavonoids showed significant positive correlations with RAC implying that both are important antioxidant bioactive compounds in peaches. We found genotypes with enhanced antioxidant capacity and a better performance than progenitors, and in consequence the best marketability. 相似文献
80.
Catherine Branger Walid Meouche André Margaillan 《Reactive and Functional Polymers》2013,73(6):859-875
Selective recognition of metal ions is a real challenge for a large range of applications in the analytical field (from extraction to detection and quantification). For that purpose, ion-imprinted polymers (IIPs) have been increasingly developed during the last 15 years on the principle of molecularly imprinted polymers (MIPs). Those imprinted materials are designed to mimic the binding sites of biological entities and assure an improved recognition of the template species. The aim of this review is to give the current state of the art in the conception of IIPs from the components to the polymerization process. Some applications of those materials will be also discussed. 相似文献