全文获取类型
收费全文 | 286篇 |
免费 | 14篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 63篇 |
金属工艺 | 36篇 |
机械仪表 | 10篇 |
建筑科学 | 15篇 |
能源动力 | 9篇 |
轻工业 | 51篇 |
水利工程 | 2篇 |
无线电 | 23篇 |
一般工业技术 | 36篇 |
冶金工业 | 25篇 |
原子能技术 | 1篇 |
自动化技术 | 24篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 11篇 |
2011年 | 14篇 |
2010年 | 9篇 |
2009年 | 14篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1998年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1970年 | 1篇 |
1968年 | 3篇 |
1961年 | 1篇 |
排序方式: 共有300条查询结果,搜索用时 0 毫秒
291.
Usama M. Attia Jeffrey R. Alcock 《The International Journal of Advanced Manufacturing Technology》2011,52(1-4):183-194
Microsystem technologies require relatively strict quality requirements. This is because their functionalities are usually dependent on stringent requirements of dimensions, masses or tolerances. When mass-producing micro-components, e.g. replication of disposable microfluidic diagnostics devices, the consistency of the produced components could be significantly affected by process variability. The variability could be associated with a specific process parameter or could be a result of process noise. This paper presents a methodology to assess and minimise process variability in micro-injection moulding, an example of well-established mass-production techniques for micro-components. A design-of-experiments approach was implemented, where five process parameters were investigated for possible effects on the process variability of two components. The variability was represented by the standard deviation of the replicated part mass. It was found that melt temperature was a significant source of variability in part mass for one of the components, whilst the other was affected by unsystematic variability. Optimisations tools such as response surfaces and desirability functions were implemented to minimise mass variability by more than 40%. 相似文献
292.
Natália de Camargo Lima de Beluci Juliana dos Santos Fabíola Azanha de Carvalho Fabio Yamashita 《应用聚合物科学杂志》2024,141(3):e54820
Research to replace synthetic polymers with biodegradable polymers is on the rise because common plastics have generated serious ecosystem problems. Films with thermoplastic starch (TPS), poly(butylene succinate) (PBS), poly(butylene adipate-co-butylene terephthalate (PBAT), and citric acid (CA) were produced by blown extrusion. They were characterized by blow-up ratio (BUR), water vapor permeability (WVP), soluble ratio (SR), water sorption isotherm, and thermogravimetric (TG) techniques. Films were uniform and showed BUR > 205%. The different proportions of PBS and PBAT significantly influenced the WVP of the films. All samples had WVP with an order of magnitude similar to other blends with high starch content (10−6 g m−1 day−1 Pa−1). CA efficiently decreased the WVP of the PBS/PBAT/TPS formulations (15/15/70% and 20/10/70% by mass) by 25.2% and 24.7% compared to the acid-free formulations. There was no significant difference in SR (19.0%–20.1%). These materials were sensitive to moisture since the equilibrium moisture content increased pronouncedly from water activity of 0.5. Films showed good thermal stability, with a maximum decomposition temperature close to pure polyesters. CA did not increase the thermal stability of blends, probably because of the low content used (0.1%). Given the outcomes of this study, these films could be deemed appropriate for applications in food packaging. 相似文献
293.
Roger Riera Jana Tauler Dr. Natàlia Feiner-Gracia Prof. Salvador Borrós Dr. Cristina Fornaguera Dr. Lorenzo Albertazzi 《ChemMedChem》2022,17(13):e202100633
Nanomedicine emerged some decades ago with the hope to be the solution for most unmet medical needs. However, tracking materials at nanoscale is challenging to their reduced size, below the resolution limit of most conventional techniques. In this context, we propose the use of direct stochastic optical reconstruction microscopy (dSTORM) to study time stability and cell trafficking after transfection of oligopeptide end-modified poly(β-aminoester) (OM-pBAE) nanoparticles. We selected different combinations of cationic end oligopeptides (arginine – R; histidine – H; and lysine – K) among polymer libraries, since the oligopeptide combination demonstrated to be useful for different applications, such as vaccination and gene silencing. We demonstrate that their time evolution as well as their cell uptake and trafficking are dependent on the oligopeptide. This study opens the pave to broad mechanistic studies at nanoscale that could enable a rational selection of specific pBAE nanoparticles composition after determining their stability and cell trafficking. 相似文献
294.
Seán T. Earley Bernadette E. Alcock John P. Lowry Carmel B. Breslin 《Journal of Applied Electrochemistry》2009,39(8):1251-1257
The application of conducting polypyrrole (PPy) and polyaniline (PAni) coated substrates in remediation of chromium, Cr(VI),
is an area of considerable interest. Here, we discuss the implementation of PPy-coated titanium as a new material for the
reduction of Cr(VI) to the less toxic trivalent state, Cr(III). An alkaline-peroxide based etching process was used to ensure
the adhesion of the PPy coatings to the underlying titanium. The PPy films showed excellent resistance to acidic Cr(VI) solutions
and remained adherent after continuous exposure to the solutions. In order to optimise the remediation process a number of
experimental parameters were investigated, including the thickness of the PPy coating, the reduction potential used in pre-treatment
of the PPy and the degree of solution agitation. The durability of the materials on exposure to the Cr(VI) test solutions
made them suitable for repeated remediation experiments. Following several test-runs, the cleanup efficiency of the material
was found to decrease slightly, however, increasing the exposure/experiment time resulted in significantly improved cleanup
ability. 相似文献
295.
Luciana Affonso Junqueira Tatiana Nunes Amaral Natália Leite Oliveira Mônica Elisabeth Torres Prado 《International Journal of Food Properties》2018,21(1):21-35
Hydrocolloid powders from Pereskia aculeata Miller were obtained by using drying in a vacuum oven and freeze-drying at different concentrations (0.5–3.0 g of hydrocolloids/100 g of aqueous phase) to produce oil-in-water emulsions. The rheological characteristics of the emulsions and their microstructures were determined. The freeze-dried hydrocolloids and higher hydrocolloid concentrations resulted in emulsions with higher viscosities. The drying method and hydrocolloid concentration influenced the thixotropic behavior, and the resulting emulsions exhibited shear-thinning behavior. Microstructural analysis showed that with increasing freeze-dried hydrocolloid concentration, the emulsions had droplets with lower average diameters and greater uniformity, suggesting greater system stability. 相似文献
296.
297.
Harsh Kumar Kanchan Bhardwaj Kamil Kuča Javad Sharifi-Rad Rachna Verma Marisa Machado Dinesh Kumar Natália Cruz-Martins 《International Journal of Food Science & Technology》2022,57(3):1386-1398
Dietary fibres and high fibre-containing foods have been a huge attraction among researchers and nutraceutical industries due to their health-promoting benefits. From Greek and Roman times, edible mushrooms are considered the ‘elixir of life’ and are often stated as a new source of dietary fibre. Containing rich sources of essential amino acids and polysaccharides, mushrooms are viewed as an advantage over protein sources of both animal and plant origin. Additionally, the ability of mushrooms to grow under controlled conditions and attain high yield in a short span has made this added-value food of extreme interest. Nowadays, mushrooms and their by-products have been used to fortify various food products as well as for use in animal feed owing to their bioactive, therapeutic and nutritional value. Hence, this review intends to highlight the current knowledge on edible mushrooms and their waste for food and feed enrichment and nutritional purposes, along with their role in human and animal diet. 相似文献
298.
Natália S. M. Ramos Denilson V. Freitas Gustavo C. S. de Souza Tailândia M. C. Belmiro André F. Lavorante Erico Teixeira-Neto Marcelo Navarro Maria C. B. S. M. Montenegro Ana Paula S. Paim 《Food Analytical Methods》2018,11(12):3371-3379
This work proposes a fluorescent probe based on CdTe quantum dots (QDs) for the determination of resveratrol in wine samples. The synthesis of cysteamine (CA) capped CdTe QD was carried out in a one-pot eco-friendly process, resorting to the electrochemical reduction of metallic tellurium powder in a graphite macroelectrode (cavity cell). The reduced species of tellurium (Te2? and Te22?) migrated to an intermediate compartment of the electrochemical cell and in the presence of a cadmium salt and organic stabilizing agent (CA), forming the colloidal dispersion of CdTe in a single step. Under optimum synthesis conditions, the fluorescence intensity of the prepared nanoparticles varied linearly with the resveratrol concentration in the range from 3.25 to 75 μg L?1 (R2?=?0.9984), with a detection limit of 0.97 μg L?1 and RSD of 3.7% (5.0 μg L?1 resveratrol, n?=?10). The method was successfully applied to the resveratrol determination in wines, with recoveries from 97.8 to 112.4%. Student’s t test was applied and no statistically significant difference was observed between the two methods (HPLC and proposed), with a confidence level of 95% (ttabulated?=?2.45 and tcalculated?=?0.38). The resveratrol determination method, by using CdTe-CA QDs as fluorescence probe, was simple, rapid, inexpensive, and sensitive. 相似文献
299.
Natália Ferrão Castelo Branco Melo Marcos Antônio Barbosa de Lima Tânia Lucia Montenegro Stamford André Galembeck Miguel A.P. Flores Galba Maria de Campos Takaki José Alberto da Costa Medeiros Thatiana Montenegro Stamford-Arnaud Thayza Christina Montenegro Stamford 《International Journal of Food Science & Technology》2020,55(11):3381-3391
This study compared the effectiveness of fungal chitosan nanocomposite, chitosan gel and chitosan nanoparticles against strawberry phytopathogenic fungi (Botrytis cinerea; Rhizopus stolonifer and Aspergillus niger). Nanoparticles were prepared by ionic gelation method and characterised by dynamic light scattering and scanning electron microscopy. The influence of the edible coatings on fungal growth was analysed in vitro and in vivo The fungal chitosan nanoparticles presented an average size = 331.1 nm (±7.21) with a narrow size distribution (PDI = 0.377) and a zeta potential = +34 mV. The edible coating made by the nanocomposite exhibited important changes in fungal morphology, and the best control of the growth of the assayed fungal strains in artificially infected strawberries. Therefore, nanotechnology brought some benefits to the conventional chitosan gel edible coating, improving its antifungal activity and forming a new eco-friendly coating. 相似文献
300.
Nat Chard 《Architectural Design》2005,75(4):22-29
Despite the obvious diversity in the ideology, materiality and character of architectural production, here it is argued that the way we (architects) draw is surprisingly uniform. One reason for this might be the limited range of materials and tools we draw with, and their generic qualities. Architect, researcher and maker Nat Chard reveals relationships between acts of drawing, making images and making ideas, by taking us through the design and manufacture of a series of analytical drawing instruments and contingent works. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献