全文获取类型
收费全文 | 316篇 |
免费 | 39篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 85篇 |
金属工艺 | 3篇 |
机械仪表 | 5篇 |
建筑科学 | 31篇 |
矿业工程 | 2篇 |
能源动力 | 23篇 |
轻工业 | 56篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 28篇 |
一般工业技术 | 36篇 |
冶金工业 | 3篇 |
原子能技术 | 11篇 |
自动化技术 | 58篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 24篇 |
2020年 | 19篇 |
2019年 | 26篇 |
2018年 | 34篇 |
2017年 | 27篇 |
2016年 | 24篇 |
2015年 | 28篇 |
2014年 | 24篇 |
2013年 | 45篇 |
2012年 | 21篇 |
2011年 | 28篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有359条查询结果,搜索用时 46 毫秒
351.
Evaluation of ground convergence and squeezing potential in the TBM driven Ghomroud tunnel project 总被引:3,自引:0,他引:3
Ebrahim Farrokh Ali Mortazavi Gholamreza Shamsi 《Tunnelling and Underground Space Technology incorporating Trenchless Technology Research》2006,21(5):504-510
One of the new components of water conveyance system in central Iran is the Ghomroud water conveyance tunnel that is being excavated by a double shield TBM. The 36 km long tunnel mainly passes through the metamorphic weak rocks of Jurassic age. Key geotechnical design issues for the tunnel, which has up to 650 m of overburden, include the potential for high ground pressure due to high in situ stress. In order to prevent the shield jamming in these weak rocks, it was necessary to evaluate the amount of ground pressure on the outer surface of TBM shield in the vicinity of the tunnel face. The stress and strain condition in the vicinity of the tunnel face has a 3D nature and it is not realistic to assume a two-dimensional stress state at the tunnel face area. In the convergence-confinement method, it is possible to simulate the tunnel face effect with an internal fictitious pressure that is imposed on the tunnel perimeter. In this study, based on the convergence-confinement method, a new method was introduced to calculate the tunnel face effect on ground pressure distribution around the tunnel face region. Then by using this method, critical areas with potential for shield jamming was predicted along the Ghomroud water conveyance tunnel. The obtained results by this method are in good agreement with the current TBM jamming situations along the Ghomroud tunnel. 相似文献
352.
353.
354.
The complex formation between quercetin (Q) and stannous chloride (SnCl2·2H2O) was studied using UV-visible, IR and 1H NMR spectroscopic techniques. Spectroscopic data suggest that Q can chelate stannous cations through both 3-hydroxy-4-carbonyl and the 3′,4′-dihydroxyl (catechol) chelation sites. The antioxidant activity of the complex was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) diammonium salt and ferric reducing antioxidant power (FRAP) methods. It was shown that radical scavenging activity and ferric reducing potential of free Q was decreased after chelation of stannous cation. 相似文献
355.
Mohamad Dosaranian-Moghadam Hamidreza Bakhshi Gholamreza Dadashzadeh 《Wireless Personal Communications》2012,65(2):293-318
The interference reduction capability of antenna arrays, base station assignment, and the power control algorithms have been considered separately as means to increase the capacity in wireless communication networks. In this paper, we propose smart step closed-loop power control (SSPC) algorithm and base station assignment method based on minimizing the transmitter power (BSA-MTP) technique for direct sequence-code division multiple access (DS-CDMA) receiver in a 2D urban environment. This receiver consists of conjugate gradient adaptive beamforming and matched filter in two stages using antenna arrays. In addition, we study an analytical approach for the evaluation of the impact of power control error (PCE) on the DS-CDMA cellular systems. The simulation results indicate that the SSPC algorithm and the BSA-MTP technique can significantly improve the network bit error rate in comparison with conventional methods. Our proposed methods can also significantly save total transmit power and extend battery life in mobile units. In addition, we show that the convergence speed of the SSPC algorithm is faster than that of conventional algorithms. Finally, we discuss two parameters of PCE and channel propagation conditions (path-loss parameter and variance of shadowing) and their effects on the capacity of the system via some computer simulations. 相似文献
356.
In the present study, nano Fe2O3/carbon black electrodes are proposed for electrochemical capacitors and the effect of nanoparticles dispersion quality on the surface morphology, nature and electrochemical properties of the electrodes are investigated. Mechanical pressing is accompanied by different mixing (mechanical and sonication) processes to prepare the electrode. Electrochemical properties of the produced nanocomposites are studied using cyclic voltammetry and electrochemical impedance spectroscopy tests in 2 M KCl electrolyte. Scanning electron microscopy is used to characterize the microstructure and the nature of the nanoparticles on the nanocomposites produced. Results obtained show that the sonicated and unsonicated 10:80:10 (CB:Fe2O3:PTFE) electrodes have specific capacitance of 22.02 and 22.35 F g−1 respectively, at scan rate of 10 mV s−1. Sonication process breaks the agglomerated particles and disperses them on the electrode surface, uniformly. This increases the specific surface area and the electrical resistance of the electrodes. The sonicated electrodes show a higher charge separation capability at electrolyte/electrode interfaces, lower ratio of outer to total charge (qO*/qT*) of 0.13 and lower current response at end potentials. Energy density was increased after the sonication process from 0.686 to 1.498 (Wh kg−1). Charge/discharge cycling results confirmed that the uniform dispersion of active material on the electrode surface postpones the electrolyte decomposition and improves the electrical conductivity during cycling. 相似文献
357.
Intan Suhairi Salleh Nur Syuhada Ali Farzad Hourfar Khairiyah Mohd Yusof Nurul Sulaiha Sulaiman Hishamuddin Jamaluddin Gholamreza Zahedi Ali Almansoori Ali Elkamel 《加拿大化工杂志》2023,101(6):3351-3361
In this paper, a troubleshooting technique is developed to provide a sequence of necessary actions during deodorizer unit failure in a palm oil refinery. This paper introduces a fuzzy expert system that incorporates the knowledge of experienced plant workers in dealing with the complex problems of the palm oil deodorizer. The presented methodology uses both qualitative and quantitative data. Qualitative data are collected from several interview sessions with the technical staff in a palm oil refinery. Quantitative data are gathered from various sources, such as control and monitoring systems. The qualitative data are analyzed to discover the possible pattern of faults in the deodorizer failure. This tool can diagnose possible faults and provide a sequence of necessary actions when deodorizer failure occurs. The obtained results show the developed deodorizer troubleshooting tool is useful to guide plant workers/operators in diagnosing the possible faults and abnormalities during the troubleshooting process, as well as to provide field training for inexperienced staff. 相似文献
358.
Seid Reza Falsafi Yong Wang Tolulope Joshua Ashaolu Minaxi Sharma Shruti Rawal Kaushika Patel Gholamreza Askari Shaghayegh Haghjooy Javanmard Hadis Rostamabadi 《Advanced functional materials》2023,33(4):2209419
Cancer is the second leading cause of death throughout the world. Nature-inspired anticancer agents (NAAs) that are a gift of nature to humanity have been extensively utilized in the alleviation/prevention of the disease due to their numerous pharmacological activities. While the oral route is an ideal and common way of drug administration, the application of NAAs through the oral pathway has been extremely limited owing to their inherent features, e.g., poor solubility, gastrointestinal (GI) instability, and low bioavailability. With the development of nano-driven encapsulation strategies, polymeric vehicles, especially those with natural origins, have demonstrated a potent platform, which can professionally shield versatile NAAs against GI barricades and safely deliver them to the site of action. In this review, the predicament of orally delivering NAAs and the encapsulation strategy solutions based on biopolymer matrices are summarized. Proof-of-concept in vitro/in vivo results are also discussed for oral delivery of these agents by various biopolymer vehicles, which can be found so far from the literature. Last but not the least, the challenges and new opportunities in the field are highlighted. 相似文献
359.
Moosavifar Maryam Zarrini Gholamreza Mashmool-barjasteh Elnaz 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(3):781-790
Journal of Inorganic and Organometallic Polymers and Materials - This study aims at the preparation of antimicrobial nanoparticles hybrid based on silver (Ag) doped Zn1?xCuxO. Zn1?xCuxO... 相似文献