全文获取类型
收费全文 | 493篇 |
免费 | 39篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 126篇 |
金属工艺 | 4篇 |
机械仪表 | 16篇 |
建筑科学 | 18篇 |
能源动力 | 34篇 |
轻工业 | 75篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 31篇 |
一般工业技术 | 129篇 |
冶金工业 | 28篇 |
原子能技术 | 1篇 |
自动化技术 | 61篇 |
出版年
2024年 | 4篇 |
2023年 | 13篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 22篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 10篇 |
2014年 | 24篇 |
2013年 | 66篇 |
2012年 | 45篇 |
2011年 | 45篇 |
2010年 | 28篇 |
2009年 | 27篇 |
2008年 | 19篇 |
2007年 | 23篇 |
2006年 | 7篇 |
2005年 | 18篇 |
2004年 | 13篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有535条查询结果,搜索用时 15 毫秒
61.
Design of an Artificial Neural Network for Analysis of Frictional Power Loss of Hydrostatic Slipper Bearings 总被引:1,自引:0,他引:1
In this study, the frictional power loss of the slippers affecting the performance of axial piston pumps and motors was investigated experimentally and theoretically. The working parameters and the slipper geometry causing minimum frictional power loss were determined. The system was also modeled by an artificial neural network. As can be seen in both approaches, the proposed neural network predictor can be employed in experimental applications of such systems. 相似文献
62.
B. Abay B. Gürbulak M. Yildirim H. Efeoglu S. Tuzemen Y. K. Yogurtçu 《Journal of Electronic Materials》1996,25(7):1054-1059
Large p-type TlInSe2, TlInTe2, and TlGaTe2 single crystals have been grown by the Bridgman-Stockbarger method, starting from stoichiometric melts. The first observations
of the switching process in p-type TlGaTe2 single crystal are reported. Current-voltage (I-V) characteristics of symmetrical In/p-TlInSe2/In, In/p-TlInTe2/In, and In/p-TlGaTe2/In structures exhibit two distinct regions: an ohmic region at low current densities and nonlinear regions (S-shape) having
negative differential resistance (NDR) at moderate and higher current densities. An electrothermal model was used to explain
the nonlinear behavior. The nonlinear behavior of the I–V curves was studied at different ambient temperatures in the 100–340K
region; the sample temperature and the threshold voltage of the NDR region were examined as a function of the current density
and the ambient temperature, respectively. The electrothermal model is a satisfactory explanation. 相似文献
63.
Polyphenol oxidase (PPO) was purified from Boletus erythropus using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. Optimum pH and temperature were found to be 8.0 and 20 °C, respectively, using 4-methylcatechol as a substrate. The enzyme was extremely stable between pH 3.0 and 9.0 after 24 h incubation at 4 °C. B. erythropus PPO was also quite stable between 10 and 30 °C after 4 h incubation. The Km and Vmax values were calculated as 2.8 mM and 1430 U/mg protein by Lineweaver–Burk curve, respectively. The enzyme activity was inhibited by sodium metabisulfite, ascorbic acid, sodium azide and benzoic acid. It was seen that the mushroom PPO was an effective biocatalyst in selected organic solvents, such as dichloromethane, dichloroethane and toluene, when catechin was used as a substrate. All data support that B. erythropus has a highly active PPO, possessing similar biochemical and kinetic characteristics to other plant PPOs. 相似文献
64.
Ozer Caglar Ebeoglugil M. Faruk Yildirim Serdar Nil Metin 《Journal of Materials Science: Materials in Electronics》2022,33(3):1511-1528
Journal of Materials Science: Materials in Electronics - In this study, ITO-coated PET was used as the substrate to create a flexible and transparent structure. a-IGZO (amorphous InGaZnO4) is... 相似文献
65.
Olga Sambalova Emanuel Billeter Oguz Yildirim Andrea Sterzi Davide Bleiner Andreas Borgschulte 《International Journal of Hydrogen Energy》2021,46(5):3346-3353
External magnetic fields affect various electrochemical processes and can be used to enhance the efficiency of the electrochemical water splitting reaction. However, the driving forces behind this effect are poorly understood due to the analytical challenges of the available interface-sensitive techniques. Here, we present a set-up based on magneto- and electro-optical probing, which allows to juxtapose the magnetic properties of the electrode with the electrochemical current densities in situ at various applied potentials and magnetic fields. On the example of an archetypal hydrogen evolution catalyst, Pt (in a form of Co/Pt superlattice), we provide evidence that a magnetic field acts on the electrochemical double layer affecting the local concentration gradient of hydroxide ions, which simultaneously affects the magneto-optical and magnetocurrent response. 相似文献
66.
Burak Yildirim 《International Journal of Hydrogen Energy》2021,46(30):16481-16493
Nowadays, with the increase in the amount of power generation related to renewable energy resources, the need for energy storage and management is raised. In this regard, the hydrogen energy plays a critical role in the development of renewable technologies. In view of the above, advanced controller design is presented in this paper to effectively perform load frequency control of islanded fuel cell microgrid based on the wind turbine, photovoltaic, fuel cell, electrolyzer, battery energy storage systems, and residential and commercial loads. The controller design is based on the determination of the controller parameters that the fuel cell microgrid system will provide the desired dynamic properties. In the proposed controller design, virtual gain and phase margin testers are added to provide the desired dynamic properties. The controller's stable parameter plane is determined with the help of the stability boundary locus method, taking into account time delay, gain, and phase margin. First, the accuracy of the stable parameter plane determined for the proposed controller design is demonstrated by means of time domain and eigenvalue analyzes. Finally, in order to show the performance of the advanced controller design and the success of the fuel cell as a backup generator, analysis studies have been carried out using actual data of solar and wind, and appropriate changes of load in studied microgrid. 相似文献
67.
Simsek Mehmet Ulvi Yildirim Okay Feyza Ozdemir Suat 《The Journal of supercomputing》2021,77(8):8563-8592
The Journal of Supercomputing - With the recent developments in Internet of Things (IoT), the number of sensors that generate raw data with high velocity, variety, and volume is tremendously... 相似文献
68.
Nina Wurzler Jan D. Schutter Ralph Wagner Matthias Dimper Vasile-Dan Hodoroaba Dirk Lützenkirchen-Hecht Ozlem Ozcan 《工业材料与腐蚀》2021,72(6):983-994
Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion. 相似文献
69.
In this study, the impacts of non‐integer order controller on the stable parameter space of the microgrid (MG) frequency control system with fixed communication time delay are investigated and discussed with the help of the stability boundary locus (SBL) method. This study proposes a non‐integer order controller for the load frequency control (LFC) of the MG systems. To that end, the load frequency model of the MG is formulated and then the characteristic equations of this model are obtained. Then, with the help of this characteristic equation, the stable parameter space of the non‐integer controller is determined with regard to different time delay (τ ) and fractional integral order values (α ) using the SBL method. In order to show the accuracy of the obtained stable parameter space, time domain and generalized modified Mikhailov (GMM) criterion studies are carried out for different values of (τ ) and (α ). According to the results obtained, the areas of stable parameter space according to different α values and τ = 1.6 are calculated as 444.8860 for α = 0.4 , 342.9728 for α = 0.7 , 259.3578 for α = 1 , 216.2541 for α = 1.3 and 159.6826 for α = 1.6 . In addition, the areas of stable parameter space according to different τ values and α = 1.4 are calculated as 784.5222 for τ = 1 , 106.3219 for τ = 2 , 29.6959 for τ = 3 and 11.5946 for τ = 4 . Despite the extreme variability arising from nature of resources that make up the MG, the designed non integer order controller with the values selected within the stable parameter space stably carries out LFC control of the MG. 相似文献
70.
Kutlu Yakup Yayık Apdullah Yildirim Esen Yildirim Serdar 《Neural computing & applications》2019,31(4):1117-1126
Neural Computing and Applications - Electroencephalography (EEG) has been used as a promising tool for investigation of brain activity during cognitive processes. The aim of this study is to reveal... 相似文献