全文获取类型
收费全文 | 317篇 |
免费 | 21篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 51篇 |
金属工艺 | 10篇 |
机械仪表 | 10篇 |
建筑科学 | 22篇 |
矿业工程 | 1篇 |
能源动力 | 36篇 |
轻工业 | 12篇 |
水利工程 | 2篇 |
石油天然气 | 5篇 |
无线电 | 45篇 |
一般工业技术 | 67篇 |
冶金工业 | 20篇 |
原子能技术 | 2篇 |
自动化技术 | 52篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 16篇 |
2013年 | 35篇 |
2012年 | 27篇 |
2011年 | 18篇 |
2010年 | 28篇 |
2009年 | 33篇 |
2008年 | 12篇 |
2007年 | 21篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有340条查询结果,搜索用时 0 毫秒
101.
In this study, abrasive wear behaviours of ZA-27 alloy and CuSn10 bronze were investigated using a purpose-built wear tester.
The ZA-27 alloy was produced by permanent mould casting. The abrasive SiC particles having 63 μm grit size was added to the
lubricant oil. The wear rate and friction coefficient of alloys were determined at the different test conditions such as sliding
distance, applied load, linear velocity and percentage SiC weight content. The wear surfaces of alloys were examined using
SEM and EDS analysis. The results showed that the wear rate of alloys decreased with the increasing of applied load and increased
with the increasing linear velocity and abrasive SiC content. It was found that the SiC particle fracture was an important
mechanism determining the friction and the wear rate of alloys. CuSn10 bronze showed higher wear resistance than ZA-27 alloy
under abrasive test conditions except at high linear velocities. 相似文献
102.
Ana Cetkovic Alessandro Bellapianta Mihai Irimia-Vladu Jakob Hofinger Cigdem Yumusak Andrea Corna Markus Clark Scharber Günther Zeck Niyazi Serdar Sariciftci Matthias Bolz Ahmad Salti 《International journal of molecular sciences》2022,23(15)
Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach has to be employed on the OPV materials before using them as retinal implants. In this study, we followed ISO standards to assess the cytotoxicity of D18, Y6, PFN-Br and PDIN individually, and as mixtures of D18/Y6, D18/Y6/PFN-Br and D18/Y6/PDIN. These materials were proven for their high performance as organic solar cells. Human RPE cells were put in direct and indirect contact with these materials to analyze their cytotoxicity by the MTT assay, apoptosis by flow cytometry, and measurements of cell morphology and proliferation by immunofluorescence. We also assessed electrophysiological recordings on mouse retinal explants via microelectrode arrays (MEAs) coated with D18/Y6. In contrast to PFN-Br and PDIN, all in vitro experiments show no cytotoxicity of D18 and Y6 alone or as a D18/Y6 mixture. We conclude that D18/Y6 is safe to be subsequently investigated as a retinal prosthesis. 相似文献
103.
Shaz Qadeer Serdar Tasiran 《International Journal on Software Tools for Technology Transfer (STTT)》2012,14(3):291-305
We give an overview of correctness criteria specific to concurrent shared-memory programs and runtime verification techniques for verifying these criteria. We cover a spectrum of criteria, from ones focusing on low-level thread interference such as races to higher-level ones such as linearizability. We contrast these criteria in the context of runtime verification. We present the key ideas underlying the runtime verification techniques for these criteria and summarize the state of the art. Finally, we discuss the issue of coverage for runtime verification for concurrency and present techniques that improve the set of covered thread interleavings. 相似文献
104.
Competitive strategy and neo-institutional scholars offer different views for studying a firm’s relationship with its environment. Competitive strategy scholars propose that a firm’s environment hosts competitive forces and that a firm’s performance is closely related with its ability to differentiate itself from its rivals. Neo-institutional scholars, on the other hand, propose that a firm’s environment hosts institutional forces and that a firm’s performance is closely related with its ability to conform to institutional norms. The research presented here builds on the premise that the propositions set forth by competitive strategy and neo-institutional scholars are complementary rather than contradictory. It empirically explores these propositions in the context of the U.S. construction industry. Research findings provide considerable empirical support for the competitive strategy scholars’ proposition that differentiation vis-à-vis rivals is positively related with a firm’s performance. On the other hand, research findings do not provide any empirical support to the neo-institutional scholars’ proposition that conformity to regulatory and societal expectations is positively related to a firm’s performance. 相似文献
105.
In this study, the basic composition and ripening profile of traditional urfa cheese made from ovine and bovine milks were investigated. While cheese made from ovine milk had higher total solids, fat-in-dry matter and total nitrogen, the titratable acidity, salt-in-dry matter, pH, total mesophilic colony count and total yeasts and moulds counts were found to be close to each other. During storage, whilst the total solids content of cheese produced from ovine milk gradually decreased, the variation in the total solids content of cheese made from bovine milk was found to be insignificant. The salt penetration into the cheeses was rapid during the first two weeks of ripening, and it continued to diffuse into the samples throughout storage. Proteolysis developed faster in the cheese made from ovine milk than in cheese of bovine milk. The former sample had higher water soluble nitrogen, nonprotein nitrogen, phosphotungustic acid soluble nitrogen, Proteose-peptone nitrogen and tyrosine levels throughout storage, and the ripening index was higher as well. 相似文献
106.
Ismail Serdar Bakal 《国际生产研究杂志》2013,51(8):2395-2412
The timing of retailer order placement is an important factor in supply chain performance in systems with uncertain end-customer demands. Retailers often prefer short order lead times, which permits the resolution of demand uncertainty prior to order placement, and reduces the risks associated with excess inventory. Suppliers, in contrast, prefer long lead times, in order to match supply output with retailer demand. These conflicting preferences create tension between a supplier and retailers regarding order timing preferences. This paper considers order timing preferences within a strategic framework involving a supplier and one of its retailers in a multiple-retailer system. We identify and explore several mechanisms a supplier can use within this framework to induce early retailer order placement and improve expected cost performance. 相似文献
107.
Ismail Serdar Bakal 《国际生产研究杂志》2013,51(11):2841-2863
We analyse the implications of order timing decisions in multi-retailer supply systems in a single period, newsvendor setting. Specifically, we investigate a supply chain with multiple retailers and a single supplier where one of the retailers is considered a preferred or primary customer of the supplier. In the base model (delayed commitment), customers order after observing demand and the supplier rations its production quantity to retailers according to a generalised uniform allocation rule. In the early-commitment model, the primary retailer commits to an order quantity prior to the selling season and receives her order in full. We compare the expected supplier and retailer profits under each of these strategies and specify conditions under which a particular commitment scheme benefits the supplier, the primary retailer, and the entire system. Our findings indicate that the supplier prefers early commitment under mild conditions, whereas the primary retailer's preference depends on the tradeoff between the supply risk and demand risk. We also compare our findings with a single-retailer system, and observe that both the supplier and the primary retailer benefit from the existence of additional customers under delayed-commitment in many contexts. 相似文献
108.
A new generation multihollow opaque polymer pigment was synthesized by suspension polymerization of “water‐in‐oil‐in‐water” emulsion method, where methyl methacrylate and ethylene glycol dimethacrylate monomer mixture was used as oil phase. The effects of surfactant and cosurfactant composition in terms of “hydrophilic/lipophilic balance” on the stability of the “water‐in‐oil” emulsion and the size of water droplets were studied. Low droplet sizes and the optimum stability were obtained with “Span 80&Tween 80” surfactant mixture at an HLB value of 8. The desired size distribution was obtained at “monomer/surfactant/water” ratio of 75.5/9.4/15.1 at an ultrasonic mixing power of 80 W lasting for 30 s. The surface morphology and hollow structure of polymer pigments were analyzed by scanning and transmission electron microscopy techniques. L*a*b color and gloss properties of polymer pigments were examined. The opacity values were assessed by contrast ratio measurements, and the pigments provided up to 97.3% opacity with 50% v/v solid content in resin. In addition, the pigments exhibited low gloss values and yielded matte films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43696. 相似文献
109.
Drilling of a hybrid Al/SiC/Gr metal matrix composites 总被引:2,自引:1,他引:1
Yahya Altunpak Mustafa Ay Serdar Aslan 《The International Journal of Advanced Manufacturing Technology》2012,60(5-8):513-517
The present study investigates the influence of cutting parameters on cutting force and surface roughness in drilling of Al/20%SiC/5%Gr and Al/20%SiC/10%Gr hybrid composites fabricated by vortex method. The drilling tests are conducted with diamond-like carbon-coated cutting tools. This paper is an attempt to understand the machining characteristics of the new hybrid metal matrix composites. The results indicate that inclusion of graphite as an additional reinforcement in Al/SiCp reinforced composite reduces the cutting force. The cutting speed and its interactions with feed rate are minimum. Feed rate is the main factor influencing the cutting force in both composites. The surface roughness value is proportional with the increase in feed rate while inversely proportional with cutting speed in both composites. For all cutting conditions, Al/20%SiC/10%Gr composite has lower surface roughness values than Al/20%SiC/5%Gr composite. The surface is analyzed using scanning electron microscope. 相似文献
110.
Önder Metin Sally Fae Ho Cemalettin Alp Hasan Can Max N. Mankin Mehmet Serdar Gültekin Miaofang Chi Shouheng Sun 《Nano Research》2013,6(1):10-18
Monodisperse Ni/Pd core/shell nanoparticles (NPs) have been synthesized by sequential reduction of nickel(II) acetate and palladium(II) bromide in oleylamine (OAm) and trioctylphosphine (TOP). The Ni/Pd NPs have a narrow size distribution with a mean particle size of 10 nm and a standard deviation of 5% with respect to the particle diameter. Mechanistic studies showed that the presence of TOP was essential to control the reductive decomposition of Ni-TOP and Pd-TOP, and the formation of Ni/Pd core/shell NPs. Using the current synthetic protocol, the composition of the Ni/Pd within the core/shell structure can be readily tuned by simply controlling the initial molar ratio of the Ni and Pd salts. The as-synthesized Ni/Pd core/shell NPs were supported on graphene (G) and used as catalyst in Suzuki-Miyaura cross-coupling reactions. Among three different kinds of Ni/Pd NPs tested, the Ni/Pd (Ni/Pd = 3/2) NPs were found to be the most active catalyst for the Suzuki-Miyaura cross-coupling of arylboronic acids with aryl iodides, bromides and even chlorides in a dimethylformamide/water mixture by using K2CO3 as a base at 110 °C. The G-Ni/Pd was also stable and reusable, providing 98% conversion after the 5th catalytic run without showing any noticeable Ni/Pd composition change. The G-Ni/Pd structure reported in this paper combines both the efficiency of a homogeneous catalyst and the durability of a heterogeneous catalyst, and is promising catalyst candidate for various Pd-based catalytic applications. 相似文献