全文获取类型
收费全文 | 926篇 |
免费 | 62篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 324篇 |
金属工艺 | 38篇 |
机械仪表 | 22篇 |
建筑科学 | 24篇 |
矿业工程 | 2篇 |
能源动力 | 41篇 |
轻工业 | 56篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 70篇 |
一般工业技术 | 163篇 |
冶金工业 | 19篇 |
原子能技术 | 2篇 |
自动化技术 | 217篇 |
出版年
2023年 | 7篇 |
2022年 | 51篇 |
2021年 | 90篇 |
2020年 | 33篇 |
2019年 | 41篇 |
2018年 | 47篇 |
2017年 | 25篇 |
2016年 | 46篇 |
2015年 | 33篇 |
2014年 | 51篇 |
2013年 | 74篇 |
2012年 | 53篇 |
2011年 | 61篇 |
2010年 | 37篇 |
2009年 | 51篇 |
2008年 | 40篇 |
2007年 | 36篇 |
2006年 | 29篇 |
2005年 | 20篇 |
2004年 | 19篇 |
2003年 | 20篇 |
2002年 | 20篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有990条查询结果,搜索用时 0 毫秒
81.
82.
Modeling of real physical processes by numerical methods is highly time-consuming and requires significant computational capacity. In some cases, tens or even hundreds of hours of high-power computing are needed to virtually model a real process that lasts one second. Processes that take many hours, such as drying, pose an even greater challenge. This problem can be solved in two ways: by using faster computers (such as computing clusters) or by significantly simplifying the modeled process (its geometry, physical phenomena, or the impact of individual factors). For this reason, all methods which speed up or minimize the number of simulations required to achieve the research objective should be analyzed. This article focuses on the latter approach, and it proposes a simple method for predicting the responses of a numerical model (values of any output parameter) to changes in input values (values of any input parameter). This method requires a base model, such as a numerical model which is qualitatively and quantitatively consistent with experimental observations, and a sensitivity analysis. This article discusses the mathematical and logical premises for the discussed model, and it proposes two methods for predicting numerical simulation results. Those methods are illustrated with examples which analyze the behavior of the Eulerian Multiphase Model and describe phase interactions based on Gidaspow's approach. The discussed example relies on data from a series of articles published by the authors in Drying Technology. This article was inspired by the observations made during a time-consuming process of modeling a spouted bed grain dryer, which was described in the above publications. The objective of this study was to discuss the advantages and possibilities created by sensitivity analyses of numerical models and to encourage their practical application. 相似文献
83.
Anna Domagala Wojciech Domagala Przemyslaw Ledwon Marta Musiol Henryk Janeczek Agnieszka Stolarczyk Piotr Kurcok Grazyna Adamus Mieczyslaw Lapkowski 《Polymer International》2016,65(12):1395-1404
New copolymer materials have been prepared by chemical grafting of oligomeric 3‐hydroxybutyric acid (OHB) onto polypyrrole (PPy) derivatives. The influence of grafting density and molecular weight of OHB brushes on the physicochemical properties of prepared copolymers was investigated. PPy substrates were prepared by FeCl3‐driven oxidative homopolymerization of N‐(2‐carboxyethyl)pyrrole or its copolymerization with pyrrole. The grafting method employed involved controlled anionic polymerization of β‐butyrolactone on pyrrole‐tethered potassium carboxylate active sites. Obtained PPy‐g‐OHB copolymers of varying grafting density and pendant polyester chain length were characterized and the observed structure–property relationships discussed. The impact of real time exposure to phosphate‐buffered saline environment was investigated and the residue products were characterized. Cross‐correlation of spectroscopic, thermal, electrical and elemental analysis data afforded comprehensive evaluation of the structure of prepared materials and their behaviour in hydrolytic medium. Erosion and degradation pathways have been identified, indicating ways to consciously tailor the physicochemical properties of these new biomimetic materials. © 2016 Society of Chemical Industry 相似文献
84.
Neil D. Hurley William H. Van Geertruyden Wojciech Z. Misiolek 《Journal of Materials Processing Technology》2009,209(18-19):5990-5995
During hot deformation of Al–Mg–Si alloys, a non-uniform microstructure is developed due to differences in localized strain. Physical simulations were performed to examine the effects of processing parameters such as deformation temperature, total reduction, rolling schedule and alloying additions on the grain structure evolution. Overall, the kinetics of recrystallization followed the traditional trends predicted by JMAK kinetics. Electron backscatter diffraction (EBSD) was used to quantify the difference in recrystallization kinetics at the sample surface and mid-thickness. The results showed that the surface showed elevated kinetics when compared to the sample mid-thickness. 相似文献
85.
Wojciech Polkowski Natalia Sobczak Rafał Nowak Artur Kudyba Grzegorz Bruzda Adelajda Polkowska Marta Homa Patrycja Turalska Merete Tangstad Jafar Safarian Elmira Moosavi-Khoonsari Alejandro Datas 《Journal of Materials Engineering and Performance》2018,27(10):5040-5053
For a successful implementation of newly proposed silicon-based latent heat thermal energy storage systems, proper ceramic materials that could withstand a contact heating with molten silicon at temperatures much higher than its melting point need to be developed. In this regard, a non-wetting behavior and low reactivity are the main criteria determining the applicability of ceramic as a potential crucible material for long-term ultrahigh temperature contact with molten silicon. In this work, the wetting of hexagonal boron nitride (h-BN) by molten silicon was examined for the first time at temperatures up to 1750 °C. For this purpose, the sessile drop technique combined with contact heating procedure under static argon was used. The reactivity in Si/h-BN system under proposed conditions was evaluated by SEM/EDS examinations of the solidified couple. It was demonstrated that increase in temperature improves wetting, and consequently, non-wetting-to-wetting transition takes place at around 1650 °C. The contact angle of 90° ± 5° is maintained at temperatures up to 1750 °C. The results of structural characterization supported by a thermodynamic modeling indicate that the wetting behavior of the Si/h-BN couple during heating to and cooling from ultrahigh temperature of 1750 °C is mainly controlled by the substrate dissolution/reprecipitation mechanism. 相似文献
86.
Electropolishing and passivation of NiTi shape memory alloy 总被引:2,自引:0,他引:2
Electropolishing of NiTi alloy has been investigated. The influence of polishing bath composition and the operating conditions instead of the conditions of the process on the quality of the surface, evaluated by AFM and SEM methods, was established. Morphologically uniform surfaces were obtained only in the case of solutions containing hydrofluoric and sulfuric acids. Electropolished samples were sterilized and thermally passivated, then their corrosion resistance was measured in Tyrode's physiological solution. It was established that already after the electropolishing the corrosion resistance of NiTi alloy increases due to the spontaneously formed TiO2 layer. The increase of the thickness of the layer during sterilization and thermal passivation causes further increase in the corrosion resistance. 相似文献
87.
Wojciech Fabianowski Ralph Jaccodine Ramesh Kodnani Raymond Pearson Piotr Smektala 《Advanced functional materials》1995,5(4):199-213
Two polymeric coatings, a silicone gel (Dow Corning 6646) and an epoxy resin (Dexter FP 4402), were glob-top coated onto representative microelectronic circuits, AT&T Triple Track Testers (TTTs), and subjected to the Pressure Cooker Test (PCT). Coupling monolayers were self- assembled on the TTTs prior to encapsulation to improve the moisture protection capabilities of the coatings. Leakage current measurements were made to evaluate the effect of applied monolayers on the moisture protection capability. The moisture protection capability was assessed in short-term and long-term leakage current measurements. MHDA (16-mercaptohexadecanoic acid) and APS (gamma-aminopropyltriethoxysilane) monolayers, in combination with silicone gel and epoxy resin respectively, exhibited very good moisture protection performance. 相似文献
88.
Chen CW Suchanek WL Shuk P Byrappa K Oakes C Riman RE Brown K Tenhuisen KS Janas VF 《Journal of materials science. Materials in medicine》2007,18(7):1413-1421
The role of citrate washing on the physical and chemical characteristics of magnesium-substituted apatites (HAMgs) was performed.
HAMgs were synthesized by a mechanochemical–hydrothermal route at room temperature in as little as 1 h, which is five times
faster than our previous work. Magnesium-substituted apatites had concentrations as high as 17.6 wt% Mg with a corresponding
specific surface area (SSA) of 216 m2/g. A systematic study was performed to examine the influence of increasing magnesium content on the physical and chemical
characteristics of the reaction products. As the magnesium content increased from 0 to 17.6 wt%, magnesium-doped apatite crystallite
size decreased from 12 to 8.8 nm. The Mg/(Mg + Ca) ratio in the product was enriched relative to that used for the reacting
precursor solution. During mechanochemical–hydrothermal reaction, magnesium doped apatites co-crystallize with magnesium hydroxide.
Citrate washing serves to remove the magnesium hydroxide phase. The concomitant increase in surface area results because of
the removal of this phase. Possible mechanisms for magnesium hydroxide leaching are discussed to explain the measured trends. 相似文献
89.
Energy Harvesting: Electric Field Assisted Microfluidic Platform for Generation of Tailorable Porous Microbeads as Cell Carriers for Tissue Engineering (Adv. Funct. Mater. 20/2018) 下载免费PDF全文
90.
Bruzda Grzegorz Polkowski Wojciech Polkowska Adelajda Nowak Rafał Kudyba Artur Książek Marzanna Lech Sebastian Karczewski Krzysztof Giuranno Donatella 《Journal of Materials Science》2022,57(28):13724-13735
Journal of Materials Science - Boron-doped molybdenum silicides have been already recognized as attractive candidates for space and ground ultra-high-temperature applications far beyond limits of... 相似文献