首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   169篇
  免费   2篇
化学工业   48篇
机械仪表   2篇
建筑科学   8篇
能源动力   2篇
轻工业   30篇
石油天然气   1篇
无线电   27篇
一般工业技术   26篇
冶金工业   2篇
自动化技术   25篇
  2024年   1篇
  2023年   6篇
  2022年   14篇
  2021年   18篇
  2020年   9篇
  2019年   9篇
  2018年   7篇
  2017年   2篇
  2016年   8篇
  2015年   2篇
  2014年   8篇
  2013年   8篇
  2012年   8篇
  2011年   10篇
  2010年   7篇
  2009年   9篇
  2008年   4篇
  2007年   11篇
  2006年   7篇
  2005年   5篇
  2004年   6篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  1999年   2篇
  1994年   1篇
排序方式: 共有171条查询结果,搜索用时 0 毫秒
71.
A preliminary investigation into the feasibility of erecting a solar chimney power plant requires a model incorporating all possible aspects of such a power plant and giving results on an hourly basis. Possible agricultural activities underneath the outer section of the solar collector would require a model predicting the changing state of the air due to evapotranspiration effects as it flows from the perimeter of the collector to the chimney in the center. The vegetation temperature and irrigation requirements need to be determined in order to ascertain how far inward crops may be planted without being subjected to heat stress. A small experimental glass roofed tunnel was constructed, planted with grass, and the changing state of the air, drawn over the grass by a fan, was determined using wet- and dry-bulb temperature measurements and the mass flow rate of the air. Starting off with a known air state inlet condition, conservation and the Penman-Monteith equations were applied to subsequent 1-m lengths of the tunnel and the state of the air at the outlet was predicted and compared with the measured state of the air. The predicted and measured values were found to be in agreement within experimental limits giving confidence in incorporating this model into the larger model of the solar chimney.  相似文献   
72.
Photonic Network Communications - To address the limitations of current radio access networks (RANs), centralized RANs adopting the concept of flexible splits of the BBU functions between radio...  相似文献   
73.
Bismuth Oxychloride (BiOCl) is a p-type indirect bandgap semiconductor with gaps in the range of 3.2–3.5 eV. In this work, BiOCl was synthesized by a simple hydrothermal method along with variation in the concentration of the capping agent citric acid to perform the tuning of the morphology of the samples. The samples were analyzed by various techniques for insight into phase formation, morphology, chemical composition etc. The as-synthesized nanomaterials exhibited extensive variation in crystal structures due to variation in the citric acid ratio. Finally the as-synthesized samples were utilized for effective photocatalytic degradation of toxic textile dyes like Rhodamine B under visible light irradiation and also for hydrogen evolution by electrochemical method. The structural tuning resulted in a noticeable increment in hydrogen evolution observed in an acidic medium for a low overpotential. The as-synthesized material can thus be utilized for waste-water remediation and various electrochemical water-splitting related applications.  相似文献   
74.
Intelligent Service Robotics - This paper proposes a hierarchical visual architecture for perceiving garments’ configuration independently from their type for the robotic unfolding task....  相似文献   
75.
Coastal ecosystems are increasingly threatened by short-sighted management policies that focus on human activities rather than the systems that sustain them. The early assessment of the impacts of human activities on the quality of the environment in coastal areas is important for decision-making, particularly in cases of environment/development conflicts, such as environmental degradation and saturation in tourist areas. In the present study, a methodology was developed for the multi-dimensional evaluation and ranking of coastal areas using a set of criteria and based on the combination of multiple criteria choice methods and Geographical Information Systems (GIS). The northeastern part of the island of Rhodes in the Aegean Sea, Greece was the case study area. A distinction in sub-areas was performed and they were ranked according to socio-economic and environmental parameters. The robustness of the proposed methodology was assessed using different configurations of the initial criteria and reapplication of the process. The advantages and disadvantages, as well as the usefulness of this methodology for comparing the status of coastal areas and evaluating their potential for further development based on various criteria, is further discussed.  相似文献   
76.
The recently developed bio-bar-code assay for the PCR-less detection of protein and nucleic acid targets has been shown to be extraordinarily sensitive, exhibiting low attomolar sensitivity for protein targets and high zeptomolar sensitivity for nucleic acid targets. In the case of DNA detection, the original assay relies on three distinct oligonucleotide strands on a single nanoparticle for target identification and signal amplification. Herein, we report the development of a new nanoparticle probe that can be used in the bio-bar-code assay, which requires only one thiolated oligonucleotide strand. This new assay relies on the ability to liberate the adsorbed thiolated oligonucleotides from the gold nanoparticle surface with dithiothreitol (DTT), which simplifies the assay and increases its quantitative capabilities. The utility of this new DTT-based system is demonstrated by detecting a mock mRNA target using both fluorescent and scanometric assay readouts. When the scanometric readout is used, the sensitivity of the assay is 7 aM and quantification can be accomplished over the low-attomolar to the mid-femtomolar concentration range.  相似文献   
77.
78.
79.
    
The effect of oregano on the oxidative stability of cottonseed oil during frying of potato chips and on the storage stability of the produced chips was studied. The ground spice or an ethanol‐derived extract thereof was added to the oil at a concentration of 2 g l?1 (dry basis) before frying. The results showed that both ground oregano and its ethanol‐derived extract decreased the rates of accumulation of conjugated dienes, polar compounds, polymerised triglycerides, dimeric triglycerides as well as p‐anisidine value (p‐AV) of the frying oil. The major decrease was observed in the accumulation of polymerised and dimeric triglycerides. The accumulation of oxidised triglycerides showed a low decrease with the addition of oregano, while the hydrolytic compounds formed during frying were not affected. No significant difference (at 95% significance level) between ground oregano and its ethanol‐derived extract was observed. The storage stability of potato chips removed from the fryer at various time intervals was estimated by the rates of increase in peroxide value and conjugated dienes of the oil absorbed in the chips. Both rates were depressed when oregano was added to the frying oil; the protective action of oregano extract was considerably greater (at 95% significance level) than that of ground oregano. Copyright © 2003 Society of Chemical Industry  相似文献   
80.
The effect of oregano on the oxidative stability of cottonseed oil during frying of potato chips and on the storage stability of the products was studied. The ground spice or an ethanol‐derived extract was added to the oil before frying. The results showed that both additives decreased the rates of accumulation of conjugated dienes, polar compounds, polymerized triacylglycerols, dimeric triacylglycerols and the p‐anisidine value of the frying oil, while the hydrolytic compounds were not affected. The major decrease was observed in the accumulation of polymerized and dimeric triacylglycerols. The storage stability of the produced chips was estimated by the rate of increase of the peroxide value and of the conjugated dienes in the oil absorbed by them. Both rates were depressed when oregano was added to the frying oil, with the protective action of oregano extract being considerably greater than that of ground oregano. The protective action of oregano extracts obtained by successive extractions with petroleum ether (PE), diethyl ether (EE) and ethanol (EtOH) and added to the chips after frying was also examined. The results showed that the EE and EtOH extracts were very effective against oxidative deterioration.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号