全文获取类型
收费全文 | 167篇 |
免费 | 10篇 |
专业分类
化学工业 | 46篇 |
金属工艺 | 3篇 |
建筑科学 | 8篇 |
能源动力 | 30篇 |
轻工业 | 32篇 |
石油天然气 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 21篇 |
冶金工业 | 10篇 |
原子能技术 | 1篇 |
自动化技术 | 18篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 20篇 |
2012年 | 3篇 |
2011年 | 18篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1996年 | 3篇 |
1991年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
1.
Neural Computing and Applications - Renewable energy sources are installed into both distribution and transmission grids more and more with the introduction of smart grid concept. Hence, efficient... 相似文献
2.
Air‐ground Matching: Appearance‐based GPS‐denied Urban Localization of Micro Aerial Vehicles 下载免费PDF全文
András L. Majdik Damiano Verda Yves Albers‐Schoenberg Davide Scaramuzza 《野外机器人技术杂志》2015,32(7):1015-1039
In this paper, we address the problem of globally localizing and tracking the pose of a camera‐equipped micro aerial vehicle (MAV) flying in urban streets at low altitudes without GPS. An image‐based global positioning system is introduced to localize the MAV with respect to the surrounding buildings. We propose a novel air‐ground image‐matching algorithm to search the airborne image of the MAV within a ground‐level, geotagged image database. Based on the detected matching image features, we infer the global position of the MAV by back‐projecting the corresponding image points onto a cadastral three‐dimensional city model. Furthermore, we describe an algorithm to track the position of the flying vehicle over several frames and to correct the accumulated drift of the visual odometry whenever a good match is detected between the airborne and the ground‐level images. The proposed approach is tested on a 2 km trajectory with a small quadrocopter flying in the streets of Zurich. Our vision‐based global localization can robustly handle extreme changes in viewpoint, illumination, perceptual aliasing, and over‐season variations, thus outperforming conventional visual place‐recognition approaches. The dataset is made publicly available to the research community. To the best of our knowledge, this is the first work that studies and demonstrates global localization and position tracking of a drone in urban streets with a single onboard camera. 相似文献
3.
Kasim Ocakoglu Ceylan Zafer Canan Varlikli Siddik Icli 《Materials Science in Semiconductor Processing》2013,16(6):1688-1694
A new method for synthesis of titanium dioxide (TiO2)-dye nanoparticles is reported. TiO2 nanocrystals were obtained at 150 and 200 °C by using chemically bonded TiO2-sensitizer dye as a precursor. Titanium tetraisopropoxide was first modified with a dye molecule and then precipitated by dropping into acidic water. A strongly colored precipitate was obtained. Hydrothermal growth of a colloidal solution was carried out in a Teflon-lined stainless steel autoclave. Dye sensitized solar cell efficiencies obtained were comparable and fill factor values were close to the analogous cells prepared by the use of conventional TiO2 paste techniques. This method allows the use of different substrates together with nanocrystalline TiO2 for many technological applications. 相似文献
4.
Didem Ag Seleci Viktor Maurer Firat Baris Barlas Julian Cedric Porsiel Bilal Temel Elcin Ceylan Suna Timur Frank Stahl Thomas Scheper Georg Garnweitner 《International journal of molecular sciences》2021,22(9)
The development of multifunctional nanoscale systems that can mediate efficient tumor targeting, together with high cellular internalization, is crucial for the diagnosis of glioma. The combination of imaging agents into one platform provides dual imaging and allows further surface modification with targeting ligands for specific glioma detection. Herein, transferrin (Tf)-decorated niosomes with integrated magnetic iron oxide nanoparticles (MIONs) and quantum dots (QDs) were formulated (PEGNIO/QDs/MIONs/Tf) for efficient imaging of glioma, supported by magnetic and active targeting. Transmission electron microscopy confirmed the complete co-encapsulation of MIONs and QDs in the niosomes. Flow cytometry analysis demonstrated enhanced cellular uptake of the niosomal formulation by glioma cells. In vitro imaging studies showed that PEGNIO/QDs/MIONs/Tf produces an obvious negative-contrast enhancement effect on glioma cells by magnetic resonance imaging (MRI) and also improved fluorescence intensity under fluorescence microscopy. This novel platform represents the first niosome-based system which combines magnetic nanoparticles and QDs, and has application potential in dual-targeted imaging of glioma. 相似文献
5.
6.
This paper reports an experimental study that aimed to investigate the effects of recycled clay brick, used as a part of fine aggregate, on mortar durability. The brick, in crushed form, was from a local brick manufacturer that salvages its off-standard products. It was used to replace 10% and 20% (by weight) of the river sand in mortar. Effects of the brick replacement on the mortar flow, compressive strength, shrinkage, freeze–thaw resistance, and alkali–silica reaction potential were investigated. The results showed that as the brick replacement level increased, the mortar flowability reduced. The 10% and 20% brick replacements had no negative effect on the mortar compressive strength and very limited effect on the mortar shrinkage. The freeze–thaw resistance of the mortar was improved by the brick replacement. However, the use of crushed brick as aggregate appeared not to reduce potential alkali–silica reaction. The microscopy study revealed the alkali–silica reaction product and associated cracking in the mortar. Additional study indicated that the brick aggregate used in the study had pessimum proportion, 30%, for the alkali–silica reaction expansion. 相似文献
7.
The present paper describes the analysis of the melting process in a single vertical shell‐and‐tube latent heat thermal energy storage (LHTES), unit and it is directed at understanding the thermal performance of the system. The study is realized using a computational fluid‐dynamic (CFD) model that takes into account of the phase‐change phenomenon by means of the enthalpy method. Fluid flow is fully resolved in the liquid phase‐change material (PCM) in order to elucidate the role of natural convection. The unsteady evolution of the melting front and the velocity and temperature fields is detailed. Temperature profiles are analyzed and compared with experimental data available in the literature. Other relevant quantities are also monitored, including energy stored and heat flux exchanged between PCM and HTF. The results demonstrate that natural convection within PCM and inlet HTF temperature significantly affects the phase‐change process. Thermal enhancement through the dispersion of highly conductive nanoparticles in the base PCM is considered in the second part of the paper. Thermal behavior of the LHTES unit charged with nano‐enhanced PCM is numerically analyzed and compared with the original system configuration. Due to increase of thermal conductivity, augmented thermal performance is observed: melting time is reduced of 15% when nano‐enhanced PCM with particle volume fraction of 4% is adopted. Similar improvements of the heat transfer rate are also detected. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
8.
The research goal of this study is to produce suitable scaffolds for tissue engineering applications. Different ratios of polyvinyl alcohol (PVA)/starch (90:10, 70:30, 50:50) and crosslinking methods have been used to prepare cryogels. Chemically crosslinked cryogels were synthesized using glutaraldehyde as the crosslinking agent. For the physically crosslinked cryogels, sodium dodecyl sulfate was used during cryogelation as the foaming agent. Chemical structure and pore morphology were demonstrated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Swelling ratio and degradation profile of the scaffolds were also determined. 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide assay and SEM were used to investigate the biocompatibility of the scaffolds and cell morphology. Genotoxicity test was performed to show DNA fragmentation. The overall results demonstrated that PVA/starch cryogels could have potentially appealing application as scaffolds for tissue engineering applications and additives affect the architecture and characteristic properties of the cryogels. 相似文献
9.
Optimization of EDGE terminal power amplifiers using memoryless digital predistortion 总被引:1,自引:0,他引:1
This paper describes a lookup-table (LUT)-based digital predistortion system usable for enhanced data for global system for mobile evolution (EDGE) handset transmitters. The system is memoryless and capable of improving average efficiency and performance in terms of the leakage power at offset frequencies and error vector magnitude. The obtainable efficiency at maximum linear output power is comparable, but at backoffs superior to commercial EDGE power amplifiers (PAs). Minimum system requirements on word length and LUT size have been investigated, which shows that a LUT having approximately 500 coefficients and a system word length of 13 bits are sufficient for EDGE. The proposed system is simple compared to basestation implementations comprising PA memory compensation and can be easily implemented in handsets in order to improve the overall system performance. The effects of antenna mismatch on system performance have been investigated 相似文献
10.
Dipl.‐Ing. J. Knochen Prof. Dr.‐Ing. U. Kunz Prof. Dr.‐Ing. T. Turek Dipl.‐Chem. S. Ceylan Prof. Dr. A. Kirschning Dr.‐Ing. I. Kampen Dipl.‐Biotechnol. M. Vielkind Prof. Dr.‐Ing. A. Kwade Dipl.‐Ing. S. Arndt Prof. Dr.‐Ing. S. Scholl 《化学,工程师,技术》2010,82(10):1799-1806
A mobile plant for practical training was developed as part of the project μ‐Consortium to integrate micro process engineering into teaching. Lab experiments in the fields of mixing and homogenous reactions, heterogeneous reactions, heat transfer and particle synthesis were worked out to impart knowledge of different process‐engineering operations. 相似文献