全文获取类型
收费全文 | 291篇 |
免费 | 11篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 29篇 |
金属工艺 | 2篇 |
机械仪表 | 6篇 |
建筑科学 | 7篇 |
矿业工程 | 6篇 |
能源动力 | 32篇 |
轻工业 | 73篇 |
水利工程 | 5篇 |
无线电 | 47篇 |
一般工业技术 | 29篇 |
冶金工业 | 6篇 |
原子能技术 | 6篇 |
自动化技术 | 44篇 |
出版年
2023年 | 7篇 |
2022年 | 3篇 |
2021年 | 15篇 |
2020年 | 17篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 23篇 |
2012年 | 24篇 |
2011年 | 21篇 |
2010年 | 32篇 |
2009年 | 27篇 |
2008年 | 20篇 |
2007年 | 24篇 |
2006年 | 17篇 |
2005年 | 6篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有302条查询结果,搜索用时 15 毫秒
1.
The applicability of fluidised-bed reactor (FBR) based sulphate reducing bioprocess was investigated for the treatment of iron containing (40-90 mg/L) acidic wastewater at 65 degrees C. The FBR was inoculated with sulphate-reducing bacteria (SRB) originally enriched from a hot mining environment. Ethanol or acetate was supplemented as carbon and electron source for the SRB. A rapid startup with 99.9, 46 and 29% ethanol, sulphate and acetate removals, in respective order, was observed even after 6 days. Iron was almost completely removed with a rate of 90 mg/L.d. The feed pH was decreased gradually from its initial value of 6 to around 3.7 during 100 days of operation. The wastewater pH of 4.3-4.4 was neutralised by the alkalinity produced in acetate oxidation and the average effluent pH was 7.8 +/- 0.8. Although ethanol removal was complete, acetate accumulated. Later the FBR was fed with acetate only. Although acetate was present in the reactor for 295 days, its oxidation rates did not improve, which may be due to low growth rate and poor attachment ability of acetate oxidising SRB. Hence, the oxidation of acetate is the rate limiting step in the sulphidogenic ethanol oxidation by the thermophilic SRB. 相似文献
2.
Mustafa Ayhan Erkan Topal 《Tunnelling and Underground Space Technology incorporating Trenchless Technology Research》2005,20(1):81-87
Tunneling projects have their uniqueness in terms of engineering problems. The expertise gained from analyzing these projects establishes a sound basis for future application. This paper conveys experiences gained during the construction and support of the design of the Dicle–Kralkizi water tunnel, Turkey. Tunnel stability problems including overbreaks and surface subsidence are evaluated. An analysis of the breakdowns, factors controlling advance rate and the overall performance of tunnel are covered. The accumulated information presented here is believed to be useful and reliable for a successful tunnel excavation in similar formations. 相似文献
3.
Erkan Yuce Shahram Minaei Oguzhan Cicekoglu 《Electrical Engineering (Archiv fur Elektrotechnik)》2006,88(6):519-525
In this paper, new floating immittance function simulators employing second-generation current controlled conveyors are proposed.
The first four of the presented circuits employ only a single grounded capacitor as passive component and can realize either
a negative or a positive floating inductor or capacitor. The last two of the proposed circuits do not employ passive components
and can realize either negative or positive floating resistances. All of the proposed circuits do not require passive element
matching. As an application, a third-order butterworth filter is realized using the proposed positive floating inductance
simulator. SPICE simulation results and large signal behavior of the filter are included. 相似文献
4.
Comparison of pool boiling CHF of a polished copper block and carbon steel block on a declined slope
Kai Wang Nejdet Erkan Laishun Wang Koji Okamoto 《Journal of Nuclear Science and Technology》2018,55(9):1065-1078
This study conducts a critical heat flux (CHF) experiment on a carbon steel block, and the block is positioned on slope that is declined at angles of 5° and 10°. The results of the carbon steel block experiment were then analyzed and compared with the results obtained from a copper block experiment that had been conducted previously at the same test facility. The comparison showed that several different types of phenomena had occurred, and the carbon steel block CHF at both 5° and 10° was much lower than that of the copper block. Detailed images of the heating surface of each material were acquired by a high-speed camera under different heat fluxes and analyzed. The carbon steel block surface generates more bubbles compared to the copper block under the same heat flux, which indicates that the carbon steel block should have a large number of nucleation sites. This causes a higher CHF. Finally, several existing theories on CHF mechanisms were also analyzed in an attempt to explain the difference of copper and carbon steel. It seemed that the contact angle alone was not sufficient to explain the large CHF decrease in the carbon steel block. 相似文献
5.
The paper deals with the singularly perturbed quasilinear initial value problem exhibiting initial layer. First the nature of solution of differential problem before presenting method for its numerical solution is discussed. The numerical solution of the problem is performed with the use of a finite-fitted difference scheme on an appropriate piecewise uniform mesh (Shishkin-type mesh). An error analysis shows that the method is first-order convergent except for a logarithmic factor, in the discrete maximum norm, independently of the perturbation parameter. Finally, numerical results supporting the theory are presented. 相似文献
6.
In this paper, a new voltage-mode (VM) first-order phase shifter (all-pass filter) employing only four NMOS transistors and
minimum number of passive elements (i.e. one resistor and one capacitor) is proposed. The proposed VM phase shifter has high
input impedance and does not require passive element matching constraints. Moreover, since only two NMOS transistors are stacked
between positive and negative supply voltages, the proposed circuit is suitable for low-voltage operation. Electronic tunability
can be provided easily by replacing the employed resistor with an NMOS transistor operating in triode region. Simulation results
based on 0.18 μm TSMC CMOS parameters with ±0.9 V supply voltages are given to demonstrate the performance of the proposed
phase shifter. 相似文献
7.
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
8.
9.
Prof. Dr. Özkan Özden Dr. Şafak Ulusoy Assoc. Prof. Dr. Nuray Erkan 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2010,5(3-4):407-412
Sea food is a major source of animal protein. Marine foods are very rich sources of mineral components. The total content of minerals in the raw flesh of marine fish and invertebrates is in the range of 0.6–1.5% wet weight. The contents of Na, K, Ca, Mg and P are up to 1 mg/100 g, whereas those of Fe, Zn, I are less than 1 mg/100 g. Mussels (Mytilus galloprovincialis) were investigated for macro and trace element composition throughout the year. Ranges of moisture, ash, protein and fat contents were 79.76–87.46 g/100 g, 1.06–2.06 g/100 g, 7.28–12.65 g/100 g and 0.33–3.49 g/100 g, respectively. While the highest protein and fat values were found in the summer (July–August), the highest moisture and ash contents were found in the winter (December–January). The contents of highest Na, K, Ca were found in the summer. Cadmium, lead and copper were found to be below the legislative limits throughout year. High levels of mercury were found in January and October. It should be discussed whether mussel may provide an alternative source of mineral for healthy nutrition. 相似文献
10.
A retrospective cross-sectional study is conducted analysing 11,771 traffic accidents reported by the police between January 2008 and December 2013 which are classified into three injury severity categories: fatal, injury, and no injury. Based on this classification, a multinomial logit analysis is performed to determine the risk factors affecting the severity of traffic injuries. The estimation results reveal that the following factors increase the probability of fatal injuries: drivers over the age of 65; primary-educated drivers; single-vehicle accidents; accidents occurring on state routes, highways or provincial roads; and the presence of pedestrian crosswalks. The results also indicate that accidents involving cars or private vehicles or those occurring during the evening peak, under clear weather conditions, on local city streets or in the presence of traffic lights decrease the probability of fatal injuries. This study comprises the most comprehensive database ever created for a Turkish sample. This study is also the first attempt to use an unordered response model to determine risk factors influencing the severity of traffic injuries in Turkey. 相似文献