全文获取类型
收费全文 | 201篇 |
免费 | 4篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 35篇 |
金属工艺 | 3篇 |
机械仪表 | 6篇 |
建筑科学 | 9篇 |
矿业工程 | 1篇 |
能源动力 | 17篇 |
轻工业 | 8篇 |
水利工程 | 3篇 |
无线电 | 23篇 |
一般工业技术 | 40篇 |
冶金工业 | 33篇 |
自动化技术 | 24篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 10篇 |
2011年 | 5篇 |
2010年 | 11篇 |
2009年 | 17篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 15 毫秒
71.
Describes the long-term treatment program and follow-up of a case of chronic, severe, multiple self-injurious behavior. The intensity, frequency, and multiplicity of self-injurious behavior in a boy 1st seen at age 61/2 yrs is unparalleled in the literature. Treatment spanned 10 mo and more than 1,000 therapy hrs. Contingent electric shock and differential reinforcement of other behavior were the primary techniques utilized. The specifics of the punishment and reinforcement contingencies were modified throughout the program as a function of the behavior, thereby allowing for evaluation of the various components of the treatment procedures. Although initial results were only partially successful, total suppression was eventually achieved in the laboratory setting. The procedures described for extending this control to the natural environment proved only moderately successful. The technical, ethical, and theoretical issues concerning the treatment of severe self-injurious behavior are discussed. It is suggested that the extrapolation of laboratory evidence to the natural setting is premature in the case of severe self-injurious behavior. Suggested criteria for the assessment of successful clinical treatment of self-injurious behavior are offered. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
72.
AbstractThis study presents the general features of the structural health monitoring (SHM) system of the long-span cable-supported bridges in Turkey, namely the First Bosphorus Bridge, the Second Bosphorus Bridge (Fatih Sultan Mehmet Bridge), the newly constructed the Third Bosphorus Bridge (Yavuz Sultan Selim) and the Osman Gazi Bridge (Izmit Bay Bridge). Due to the critical function of the bridges in the transportation networks of Istanbul, structural health under extreme and operational load cases without interruption of their operation is essential. The SHM systems are already available and in use for the First and Second Bosphorus Bridges; however, the Yavuz Sultan Selim and the Osman Gazi Bridges, only have the preliminary SHM systems established. General preferences of the current and planned SHM systems of the bridges are given based on the monitoring objectives and requirements. Data collected from the SHM systems are also exhibited as an illustration for structural modal identification of the First Bosphorus Bridge. Based on the experiences from the current SHM systems, future works and planning are recommended to effectively design new SHM system and to efficiently update the current ones. 相似文献
73.
74.
75.
Selcuk Erkekol I. Hakki Gucuyener Mustafa Versan Kok 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(9):885-892
The objective of this study was to select the proper drilling fluid type and composition for drilling stable holes through the problems of the selected formations. This study was performed on shale samples taken from 10 wells in which hole instability was encountered to various extents during drilling the Germav formation. Both ionic and polymer inhibitions were utilized in formulating the proper drilling for the Germav formation. Ionic inhibition was obtained using KCl and NaCl. Polyanionic polymer (Pac-L) was used for providing the polymer encapsulation. Experimental results indicated that KCl is superior to NaCl in providing ionic inhibition. Both salts lowered the interaction between the drilling fluid and Germav formation, but better results were obtained with KCl. Minimum salt concentration up to 15% yields more inhibitive environment. Polymer inhibition tests indicated that minimum Pac-L concentration required for maintaining the polymer inhibition was about 2 lb/bbl for both systems. In conclusion, KCl/encapsulating polymer system seems to be the most proper water: base drilling fluid available for Germav formation achieving the required wellbore stability. The fluid loss and suspending properties of the proposed system must be controlled using the modified starch and XC polymer. 相似文献
76.
Murat Dilmec H. Selcuk Halkaci Fahrettin Ozturk Haydar Livatyali Osman Yigit 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2689-2700
In this study, the effects of sheet thickness and anisotropy of AA2024-T4 on forming limit curve (FLC) are experimentally investigated according to ISO 12004-2 standard. A new limit strain measurement method is proposed by using the grid analysis method so as to determine limit strains conveniently and reliably. In addition to the regular test specimens, various widths are added to enhance the FLC’s accuracy at the plane strain condition (PSC). The accuracy and reliability of the proposed method are verified for different materials. Results illustrate that an increase in the sheet thickness increases the FLC level. The additional experiments for additional widths improve the accuracy of the FLC at the PSC, and the position of the lowest major strain value differs from the literature. However, the effect of anisotropy on the FLC is found to be insignificant. Finally, experimental and numerical case studies are carried out for conventional deep drawing, stretch drawing, and hydraulic bulge processes. Results reveal that different FLCs are necessary for different thicknesses for accurate predictions. 相似文献
77.
Kerem Goren 《The Journal of Supercritical Fluids》2010,51(3):420-196
Creating polymer foams with controlled pore size and pore density is an important part of controlling foam properties. The addition of nanoparticles has been shown to cause heterogeneous nucleation and can be used to reduce pore size. In the current study, the effects of filler size and filler surface chemistry on pore nucleation in silica/PMMA nanocomposites are investigated. It was found that as the nanofiller size decreased, the pore density increased by a factor of 2-3 decades compared to that of unfilled PMMA (pore cell densities above 1012 cells/cm3 were obtained). In addition, fluorination of the silica nanoparticle surface led to decreased pore size without changing the degree of silica aggregation and overall density. By monitoring the pore density as a function of pressure, a qualitative comparison was obtained that showed that fluorination of the nanoparticle reduced the critical free energy of nucleation. 相似文献
78.
Yasin Şöhret Selcuk Ekici T. Hikmet Karakoc 《International Journal of Hydrogen Energy》2018,43(23):10842-10847
Ramjet engines are widely-used devices in the defence industry and have military applications. These engine types, preferred in many fields, are known to act according to the laws of thermodynamics. For this reason, exergy analysis methodology is a beneficial tool for assessing the performance of a ramjet engine, as well as other energy conversion systems. The present study aims to introduce a performance analysis of a hydrogen fueled ramjet engine within the framework of the first and second laws of thermodynamics. At the end of the study, the exergy efficiencies of inlet, combustion zone and nozzle are found to be 3.88%, 7.62%, and 0.03%, respectively, whereas the exergy efficiency of a ramjet engine is 8.85%. The introduced methodology and the results obtained from the current study may be useful for anybody who is interested in thermal sciences and aero-propulsion technologies. 相似文献
79.
G. Chehade M.E. Demir I. Dincer B. Yuzer H. Selcuk 《International Journal of Hydrogen Energy》2018,43(27):12049-12058
In this research paper, an experimental investigation of photoactive material titanium dioxide (TiO2) coated on 180 cm2 316 stainless steel anode is undertaken to study the photoresponse on photoelectrochemical (PEC) hydrogen production. The TiO2 nanoparticles are first prepared via sol-gel method. A large surface 316 stainless steel anode is coated with TiO2 nanoparticles by a dip coating apparatus at a withdraw rate of 2.5 mm/s. The nanoparticles are carried on the stainless steel substrate by two-step annealing procedure. The potentiostatic studies confirm the photoactivity of TiO2 nanoparticles in a photoelectrochemical reactor when exposed to solar ultraviolet (UV) light. The photon to current efficiency measurements carried out on the PEC reactor with TiO2 coated large surface stainless steel as photoanode demonstrate a significant increase of photoresponse in UV light compared to the uncoated stainless steel prepared under similar conditions. Upon illumination at a power density of 600 W/m2, the hydrogen production is observed in TiO2 coated stainless steel substrate at a measured rate of 51 ml/h while no illumination conditions show a production rate of 42 ml/h. In comparative assessments, the TiO2 coated substrate shows an increase in photocurrent of 10 mA with an energy efficiency of 1.32% and exergy efficiency of 3.42% at an applied potential of 1.6 V. The present results show a great potential for titanium nanoparticles semiconductor metal oxide in photoelectrochemical hydrogen production application. 相似文献
80.
Renewable energy is the energy generated from natural resources such as sunlight, wind, rain, tides and geothermal heat which are renewable. Energy resources are very important in perspective of economics and politics for all countries. Hence, the selection of the best alternative for any country takes an important role for energy investments. Among decision-making methodologies, axiomatic design (AD) and analytic hierarchy process (AHP) are often used in the literature. The fuzzy set theory is a powerful tool to treat the uncertainty in case of incomplete or vague information. In this paper, fuzzy multicriteria decision- making methodologies are suggested for the selection among renewable energy alternatives. The first methodology is based on the AHP which allows the evaluation scores from experts to be linguistic expressions, crisp, or fuzzy numbers, while the second is based on AD principles under fuzziness which evaluates the alternatives under objective or subjective criteria with respect to the functional requirements obtained from experts. The originality of the paper comes from the fuzzy AD application to the selection of the best renewable energy alternative and the comparison with fuzzy AHP. In the application of the proposed methodologies the most appropriate renewable energy alternative is determined for Turkey. 相似文献