全文获取类型
收费全文 | 297篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 78篇 |
金属工艺 | 9篇 |
机械仪表 | 9篇 |
建筑科学 | 16篇 |
矿业工程 | 4篇 |
能源动力 | 28篇 |
轻工业 | 57篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 35篇 |
冶金工业 | 22篇 |
自动化技术 | 26篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 13篇 |
2013年 | 21篇 |
2012年 | 22篇 |
2011年 | 25篇 |
2010年 | 14篇 |
2009年 | 27篇 |
2008年 | 16篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1970年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
1.
Downhole pumps are being used increasingly more often in low-enthalpy geothermal wells. The depth at which these pumps are installed depends on the physical and chemical characteristics of the geothermal fluid, the production flow rate, and the reservoir pressure and permeability. In this study we have investigated the factors affecting pump setting depths in low-temperature, liquid-dominated geothermal systems and defined the relationship between flow rate and pressure drawdown based on multi-rate test results. The methodology proposed was applied to the Balcova-Narlidere geothermal field, Turkey. It was found that the most important parameters for determining the capacity and setting depth of a downhole pump were flow performance, non-condensable gas concentration, and temperature. The implementation of the methodology is illustrated. 相似文献
2.
The viability of developing an SiC fibre-reinforced titanium/titanium aluminide hybrid matrix composite was explored. The
hybrid composites are expected to be used at temperatures beyond those attainable in conventional titanium matrix composites
while improving the damage tolerance of the titanium aluminide matrix composites. The room-temperature mechanical characteristics
studied were tensile strength, fracture toughness, low-cycle fatigue life and fatigue crack growth rate. The mechanisms of
damage initiation and propagation under various loading conditions were also characterized. The directions for developing
a satisfactory composite with hybrid titanium/titanium aluminide matrix are also addressed. 相似文献
3.
Organo-functional silanes which were able to form chemical bonds with kaolinite and could also have an affinity to the materials of concern here, were studied by the sol-gel process. Polymethacrylate with trialkoxy silyl functional groups were prepared, hydrolysed and co-condensed with kaolinite. The progress of the hydrolysis, which proceeded very slowly, was followed by Karl-Fischer titration. Thermal behavior was investigated by differential thermal analysis. The extent of the reaction leading to network formation was qualitatively followed by Fourier transform-infrared spectroscopy and X-ray diffraction. Free-radical polymerization was carried out ultrasonically in the presence of a catalyst. Trimethoxy silane end-capped silane was found to be covalently bonded to kaolinite. The copolymers, with various amounts of kaolinite, were then hydrolysed and co-condensed in the presence of a catalyst to yield sol-gel materials which have a controllable combination of properties of both the polymer and kaolinite. 相似文献
4.
Dual-phase(DP) steels with different martensite contents were obtained by appropriate heat treatment of an SAE1010 structural carbon steel,which was cheap and widely used in the construction industry. The corrosion behavior of DP steels in con-crete was investigated under various tempering conditions. Intercritical annealing heat treatment was applied to the reinforcing steel to obtain DP steels with different contents of martensite. These DP steels were tempered at 200,300,and 400°C for 45 min and then coo... 相似文献
5.
Uur Sar Sedat Aan lhan Aksoy Kutalm
Güven Nermin Kahveci 《Journal of Materials Processing Technology》2004,150(3):208-214
In this systematic study, dispersion-strengthening effect of the Cu–25.91Mn (wt.%), Cu–26.62Mn–8.99Al (wt.%), Cu–22.17Mn–12.32Zn (wt.%) ingot alloys have been investigated. Samples were homogenized at a high fixed temperature in different periods and cooled with different cooling rates. After processes, microanalysis of the samples were interpreted by using scanning electron microscope (SEM) and weight percentages of the elements of the occurrence phases in the samples obtained by using electron dispersion spectroscopy (EDS) technique. Additionally, some characteristic properties of the heat treated samples with different conditions of Cu–Mn, Cu–Mn–Al, Cu–Mn–Zn ingot alloys were also discussed. 相似文献
6.
A 4-week UNESCO-sponsored mission to the Department of Architecture, Karadeniz Technical University in Eastern Turkey, gave an opportunity to apply ergonomics techniques to some aspects of that country's domestic washbasin design. The study was intended to provide experience in questionnaire design and administration, in the application of psycho-physical methods, and to highlight the importance of determining user characteristics and preferences with regard to the built environment. A field study elicited information on dimensions and positioning of existing wash-basins and ancillary equipment and the opinions of users as to the suitability of these features in relation to the activities performed. A laboratory study, using an adjustable rig permitting variation in the heights of basin, taps and mirror/shelf, followed. The data obtained on preferred heights of these items led to the conclusions that basin height should be increased to between 95 and 100 cm to satisfy the majority of users; tap height above the basin should be reduced to about 11 cm; the shelf and lower edge of a mirror sited above the basin should be 136 cm above the floor; and a clear space of 110 cm should be available between the front of the basin and a wall or other obstruction. Suggestions on other design aspects of the bathroom, resulting from the study, are discussed. 相似文献
7.
Nazish Jahan Saba Aslam Khalil ur Rahman Tuba Fazal Fareeha Anwar Rubab Saher 《Journal of Experimental Nanoscience》2016,11(1):72-80
Nanotechnology is a promising technique to increase the bioavailability of herbal medicines. This paper presents the nanosuspension approach for increasing the aqueous solubility and thereby bioactivity of important herbal extracts. Nanosuspensions of the seeds of three plants extract (Silybum marianum, Elettaria cardamomum and Coriandrum sativum) were prepared by using polyvinyl alcohol (1.5% w/v) as a stabiliser. Prepared nanoparticles were characterised by scanning electron microscope. Activity of nanosuspension formulation was assessed by using four in vitro antioxidant assays. S. marianum, E. cardamomum and C. sativum particle size was observed to fall in range of 446.1 ± 112.6, 456.63 ± 339.2 and 432.1 ± 172.8 nm, respectively, most of the particles were having spherical shape and smooth topology. These synthesised nanoparticles were found to be more effective against quenching free radical than their crude extracts and standards [butylated hydroxyl toluene and ascorbic acid]. C. sativum nanosuspension showed most free radical scavenging potential against 2,2-diphenyl-1-picrylhdrazyl (DPPH) and superoxide free radical scavenging assays (IC50 0.59 ± 0.01 and 0.81 ± 0.11 mg/ml). S. marianum nanosuspension was found to be most effective against DPPH radicals scavenging (IC50 0.34 ± 0.02 mg/ml). It was concluded that nanosuspension of herbal medicines potentiates the antioxidant potential. 相似文献
8.
Conducting carbon/polymer composites as a catalyst support for proton exchange membrane fuel cells 下载免费PDF全文
Carbon/poly(3,4‐ethylene dioxythiophene) (C/PEDOT) composites are synthesized by in situ chemical oxidative polymerization of EDOT monomer on carbon black in order to decrease carbon corrosion that occurred in carbon‐supported catalysts used in proton exchange membrane fuel cell. The effects of different dopants including polystyrene sulfonic acid, p‐toluenesulfonic acid and camphorsulfonic acid with the addition of ethylene glycol or dimethyl sulfoxide on the properties of the composites are investigated. The synthesized composites are characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, surface area analysis and scanning electron microscope. Electrical conductivity is determined by using the four‐point probe technique. Electrochemical oxidation characteristics of the synthesized C/PEDOT composites are investigated by cyclic voltammetry by applying 1.2 V for 24 h. The composite prepared at 25 °C with p‐toluenesulfonic acid and ethylene glycol shows the best carbon corrosion resistance. Platinum‐supported catalyst by using this composite was prepared using microwave irradiation technique, and it was seen that the prepared catalyst did not significantly lose its hydrogen oxidation and oxygen reduction reaction activities after electrochemical oxidation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Erkan Ertürk Mustaf Ali Tezeren Tahir Tilki Tuba Erdogan Ahmet C Gren 《Polymer International》2012,61(5):795-799
The readily available mixed‐valent iron trifluoroacetate complex [Fe2IIIFeII(µ3‐O)(O2CCF3)6(H2O)3] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end‐group analysis by 19F NMR spectroscopy, a Lewis acid (LA⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry 相似文献
10.
Ebru Kuyumcu Savan Büşra Aksoy Öznur Güngör Süleyman Köytepe Turgay Seçkin 《国际聚合物材料杂志》2016,65(8):402-408
Polyurethane films were synthesized by 3,4-divanillyltetrahydrofuran and different diisocyanates. These prepared polyurethanes were characterized by FT-IR, DSC, DTA, and TGA techniques. For the amperometric applications, synthesized polyurethanes exhibited suitable Tg (°C), good thermal stability and good adhesive properties. In addition, because of their interesting film properties, attempts were made to prepare dopamine-sensing electrode. For this reason, selectivity of film-coated electrodes obtained from the chemically prepared polyurethanes toward electroactive and nonelectroactive species were examined by means of DPV technique. From the electrochemical results obtained, it has been demonstrated that the PU-1-coated electrode can be used for the development of biomedical sensor. 相似文献