全文获取类型
收费全文 | 501篇 |
免费 | 10篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 15篇 |
综合类 | 1篇 |
化学工业 | 88篇 |
金属工艺 | 5篇 |
机械仪表 | 10篇 |
建筑科学 | 31篇 |
矿业工程 | 3篇 |
能源动力 | 31篇 |
轻工业 | 18篇 |
水利工程 | 5篇 |
无线电 | 39篇 |
一般工业技术 | 108篇 |
冶金工业 | 61篇 |
原子能技术 | 5篇 |
自动化技术 | 95篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 19篇 |
2019年 | 18篇 |
2018年 | 21篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 40篇 |
2012年 | 22篇 |
2011年 | 30篇 |
2010年 | 25篇 |
2009年 | 15篇 |
2008年 | 14篇 |
2007年 | 17篇 |
2006年 | 14篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有515条查询结果,搜索用时 15 毫秒
71.
Adaptive neural net (ANN) model of hot metal desulphurization is first optimized by various search methods including the golden section search and Davies-Swann-Campey methods. Logarithmic preprocessing of input data leads to a further improvement in generalization ability of the net. Genetic adaptive search (GAS) method is used to optimize the mathematical model for desulphurization and when the input data are preprocessed with this optimized model and fed into an artificial neural net, the generalization ability of the net becomes even better. Best results are obtained when using GAS to optimize the interconnection weights during the training phase, while training data are preprocessed through a mathematical model already optimized by GAS. For every process several options presented by a combination of ANN and GAS must be systematically investigated before choosing the ultimate model for predictions on shop floor. 相似文献
72.
Novel vanadium oxide based catalyst derived from the open-framework solid, [Co3V18O42(H2O)12(XO4)]·24 H2O (X = V, S) (1) catalyses oxidative dehydrogenation of propane to propylene. Catalyst activity was evaluated in the temperature range 250–400 °C with varying gas hourly space velocity (GHSV). At 350 °C and GHSV of 9786 h?1 and at 1.3% propane conversion the selectivity to propylene was 36.8%. The major products obtained were propylene and CO x (CO2 and CO). The ratio of the propylene to CO x depended directly on the catalytic sites present. Thus, as the amount of the catalyst was decreased, the conversion decreased with an increase in the propylene selectivity and a decrease in the selectivity to carbon oxides—CO x . The catalyst has been characterized by temperature programmed reduction and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). 相似文献
73.
Biswajit Deb Bibek Jyoti Borah Bhaskar Jyoti Sarmah Babulal Das Dipak Kumar Dutta 《Inorganic chemistry communications》2009,12(9):868-871
The hexa-coordinated chelate complexes of the type [Ru(CO)2Cl2(P-P)](1a,b) [where P-P = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene(a) and [bis(2-diphenylphosphinophenyl)ether(b)] have been synthesized by reacting the polymeric precursor [Ru(CO)2Cl2]n with the ligands in 1:1 molar ratio. The complexes 1a,b are characterized by elemental analyses, Mass, IR and NMR spectroscopy together with the single crystal X-ray structure determination of 1a. The compound 1a crystallizes in a monoclinic system with space group C2/c showing a slightly distorted octahedral geometry around the Ru centre. The complexes 1a and 1b are thermally stable up to 300 °C and exhibit high catalytic activity in transfer hydrogenation of aldehyde and ketones to corresponding alcohols. The complexes 1a and 1b show much higher catalytic activity for the hydrogenation of aldehyde than ketones. In general, the catalytic efficiency of 1b is higher compared with 1a. 相似文献
74.
Jayanta Deb Mondol David McIlveen-Wright Sina Rezvani Ye Huang Neil Hewitt 《Fuel》2009,88(12):2495-2506
The techno-economic evaluation of four novel integrated gasification combined cycle (IGCC) power plants fuelled with low rank lignite coal with CO2 capture facility has been investigated using ECLIPSE process simulator. The performance of the proposed plants was compared with two conventional IGCC plants with and without CO2 capture. The proposed plants include an advanced CO2 capturing process based on the Absorption Enhanced Reforming (AER) reaction and the regeneration of sorbent materials avoiding the need for sulphur removal component, shift reactor and/or a high temperature gas cleaning process. The results show that the proposed CO2 capture plants efficiencies were 18.5–21% higher than the conventional IGCC CO2 capture plant. For the proposed plants, the CO2 capture efficiencies were found to be within 95.8–97%. The CO2 capture efficiency for the conventional IGCC plant was 87.7%. The specific investment costs for the proposed plants were between 1207 and 1479 €/kWe and 1620 €/kWe and 1134 €/kWe for the conventional plants with and without CO2 capture respectively. Overall the proposed IGCC plants are cleaner, more efficient and produce electricity at cheaper price than the conventional IGCC process. 相似文献
75.
76.
Wireless Personal Communications - Detection of heart sound and analysis is required to determine heart rate, heart sound components (S1, S2 and murmurs), and is an important step to... 相似文献
77.
Stone columns, which are frequently employed to stabilize the liquefiable soil, are susceptible to accumulation of soil particles. The progressive accumulation of the soil particles causes clogging of the stone column which decreases its drainage capacity. The stone column can be encased with geotextile to sustain its long term drainage function. The encasement prevents the movement of the soil particles into the stone pores. In the present paper, a mathematical model is presented to assess the filtration performance of the geotextile encasement to prevent the clogging. The filtration capacity of the geotextile is related to its maximum pore size, porosity and soil characteristics. It is observed that the encased stone column dissipates the excess pore pressure at a faster rate compared to the stone column without encasement. The peak maximum excess pore water pressure (Umax) is not significantly affected due to selection of the opening size of the geotextiles for single earthquake. However, the opening size can significantly affect the peak Umax value for multiple earthquakes. Depending on the capture coefficient of the stone column, the clogging can be fully prevented for higher hydraulic gradient if geotextile with maximum opening size in between D10 to D5 is used as encasement. 相似文献
78.
Selective fractionation of cholesterol from whole milk powder: optimisation of supercritical process conditions
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jayakumar Chitra Shyamali Deb Hari N. Mishra 《International Journal of Food Science & Technology》2015,50(11):2467-2474
Supercritical fluid extraction (SCFE) of cholesterol from whole milk powder (WMP) was investigated in this study. The combined effects of temperature (40–80 °C) and pressure (150–250 bar) on the efficacy of cholesterol extraction (mg 100 g?1), modifications in the fat content (FC) (%) and solubility index (SI) (%) of WMP were studied and optimised by the application of response surface methodology (RSM). Variations in the free fatty acids (FFAs) (mg oleic acid per 100 g of milk fat) and lightness value (L*) were also investigated after SCFE process. About 55.8% reduction in cholesterol was achieved at the optimised condition of 68 °C, 207 bar with 40 min static time and 2 h dynamic time at flow rate of 6 L min?1. Extraction at the optimised conditions maximised the yield of cholesterol while retaining the FC, SI, FFA and L* at moderate limits of 23.7%, 85.1%, 7.7 mg per 100 g milk fat and 95.4, respectively. 相似文献
79.
Md. Mahbubur Rahman Narayan Chandra Deb Nath Jae-Joon Lee 《Israel journal of chemistry》2015,55(9):990-1001
Electrochemical impedance spectroscopy (EIS) is a very powerful tool for elucidation of charge transfer and transport processes in sensitization-based solar cells (e.g., dye-sensitized solar cells [DSSCs], quantum dot-sensitized solar cells [QDSSCs], and perovskite solar cells [PSCs]). EIS measures the electrochemical response to small amplitude AC signals over a wide range of frequencies. Analysis of the EIS response provides information about the corresponding parameters of the cells. Here, we review the fundamentals of EIS, charge transport kinetic processes, and equivalent circuit models of sensitization-based solar cells and use these concepts to explain the EIS spectra of DSSCs, QDSSCs, and PSCs. This review will be very useful for understanding the fundamental charge transfer and transport processes in different sensitization-based solar cells and the use of an equivalent circuit model to interpret the observed charge transfer and reactions. 相似文献
80.
Wireless Networks - The rapid escalation of user traffic and service innovation has made the deployment of small cell base stations essential for eventually decreasing energy consumption in future... 相似文献