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   68篇
  免费   2篇
  国内免费   2篇
电工技术   1篇
化学工业   17篇
金属工艺   2篇
建筑科学   2篇
能源动力   3篇
轻工业   7篇
无线电   13篇
一般工业技术   12篇
冶金工业   8篇
原子能技术   1篇
自动化技术   6篇
  2023年   3篇
  2022年   2篇
  2021年   7篇
  2020年   3篇
  2019年   7篇
  2018年   3篇
  2017年   2篇
  2016年   4篇
  2013年   2篇
  2012年   2篇
  2011年   1篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   3篇
  1999年   1篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1982年   6篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
排序方式: 共有72条查询结果,搜索用时 15 毫秒
51.

Industrial/organizational (I/O) psychology, the subfield of psychology applied to the context of work, has been criticized for being dominated by U.S. authors because this dominance could prevent the generalizability of results and the enrichment of theories, paradigms, and approaches by researchers from other parts of the world. Previous estimates on the extent of the U.S. dominance are, however, likely restricted in scope, outdated, and likely biased by non-U.S. researchers who were socialized in the U.S. or received help by U.S. co-authors. As such, we measured the level of U.S. dominance by analyzing 5626 papers published from the top ten journals of the field of I/O psychology in the last eleven years and their authors. The results show that the U.S. dominance continues, although the internationalization of I/O psychology has steadily increased. An additional analysis of the gender distribution across our sample revealed that female first authorship is slightly more common among authors with no U.S. affiliation. We suggest several steps to further increase the level of internationalization.

  相似文献   
52.
Scientometrics - Researchers’ careers depend on publishing papers. There are explicit expectations (e.g., paper structure) that affect editors’ and reviewers’ perceptions of...  相似文献   
53.
Overall reliability or global availability is an important parameter in the design of the large scale computer communication systems having efficient resource sharing amongst the various computer centres. In order to design an optimal topological layout of the various links connected between the set of various geographically-distant computers, one should have knowledge of the cost and reliability of all the possible links and the maximum permissible cost. In this paper a heuristic algorithm is presented for obtaining an optimal network topology which gives the maximum overall reliability of the computer communication network. The method is general and is easily implemented on a computer.  相似文献   
54.
LR-115 (type II)-based radon-thoron discriminating twin-chamber dosemeters have been used for estimating radon ((222)Rn) and thoron ((220)Rn) concentrations in dwellings of south-western Punjab, India. The present study region has shown pronounced cases of cancer incidents in the public [Thakur, Rao, Rajwanshi, Parwana and Kumar (Epidemiological study of high cancer among rural agricultural community of Punjab in Northern India. Int J Environ Res Public Health 2008; 5(5):399-407) and Kumar et al. (Risk assessment for natural uranium in subsurface water of Punjab state, India. Hum Ecol Risk Assess 2011;17:381-93)]. Radon being a carcinogen has been monitored in some dwellings selected randomly in the study area. Results show that the values of radon ((222)Rn) varied from 21 to 79 Bq m(-3), with a geometric mean of 45 Bq m(-3) [geometric standard deviation (GSD 1.39)], and those of thoron ((220)Rn) from minimum detection level to 58 Bq m(-3) with a geometric mean of 19 Bq m(-3) (GSD 1.88). Bare card data are used for computing the progeny concentration by deriving the equilibrium factor (F) using a root finding method [Mayya, Eappen and Nambi (Methodology for mixed field inhalation dosimetry in monazite areas using a twin-cup dosemeter with three track detectors. Radiat Prot Dosim 1998;77(3):177-84)]. Inhalation doses have been calculated and compared using UNSCEAR equilibrium factors and by using the calculated F-values. The results show satisfactory comparison between the values.  相似文献   
55.
This paper presents research findings on the tribological performance of electrodeposited coatings subject to nano-lubricants with the addition of nano-Al_2O_3 and graphene and Ni/nano-Al_2O_3 composite coatings. Electrodeposited coatings were produced by using a pulse electrodeposition method. Tribological experiments were conducted by using a linear reciprocating ball on flat sliding tribometer. Experimental results confirmed that the wear and friction resistance properties were significantly enhanced by doping of nano-effects in the lubricating oil and composite coating. The addition of Al_2O_3 nanoparticles in the lubricating oil showed the best tribological properties, followed by Ni–Al_2O_3 composite coatings and nano-oil with graphene. The surface morphology and microstructure of electrodeposited coatings were examined by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The wear mechanisms of these coatings subjected to tribological testing were investigated by post-test surface analyses. This research provides a novel approach to design durable nano-coatings for tribological applications in various industries such as automotive,aerospace, locomotive and renewable energy technologies.  相似文献   
56.
Synthetic polymers are ubiquitous materials widely used in construction, automotive, electronics, and countless commercial products. With the growing trend of polymer applications in everyday life, upholding the rigorous fire safety regulations has become a matter of concern. In this regard, numerous studies have been conducted for improving the fire retardancy of polymers, mainly through incorporating a diverse group of fire-retardant compounds into polymer-based composites. This review article aims to present a comprehensive overview of recent advances in the fire-retardant categories for polymeric materials especially emphasizing the nanosized fire retardants. Along with an attempt to focus attention on the consumption of conventional and possibly harmful fire retardants, potential eco-friendly alternatives are represented. A detailed discussion on the flame retardation mechanisms and conventional fire characterization techniques are also discussed.  相似文献   
57.
58.
Since K fixation in soils is largely a function of clay mineralogy, an effort was made to elucidate the influence of mineralogical variations in soil clays on K fixation, under the moisture-temperature regimes usually prevalent in tropical upland rice soils. Beidellitic clay turned out to be the most severe fixer of addedK (80%), followed by vermiculitic (69%) clays. Fixation is not appreciable (< 15%) in clays consisting of montmorillonite, x-ray amorphous material, chlorite, hydrous mica, kaolinite and halloysite. Fixation by beidellite and vermiculite clays is reduced by the simultaneous occurrence of other mineral species.  相似文献   
59.
Water quality estimation in fresh and marine water systems with in situ above-water spectroscopy requires measurement of the volume reflectance (rho(v)) of water bodies. However, the above-water radiometric measurements include surface reflection (L(r)) as a significant component along with volume reflection. The L(r) carries no information on water quality, and hence it is considered as a major source of error in in situ above-water spectroscopy. Currently, there are no methods to directly measure L(r). The common method to estimate L(r) assumes a constant water surface reflectance (rho(s)) of 2%, and then subtracts the L(r) thus calculated from the above-water radiance measurements to obtain the volume reflection (L(v)). The problem with this method is that the amount of rho(s) varies with environmental conditions. Therefore, a methodology was developed in this study for direct measurement of water volume reflectance above water at nadir view geometry. Other objectives of this study were to analyze the contribution of L(r) to the total water reflectance under various environmental conditions in a controlled setup and to develop an artificial neural network (ANN) model to estimate rho(s) from environmental conditions. The results showed that L(r) contributed 20-54% of total upwelling radiance from water at nadir. The rho(s) was highly variable with environmental conditions. Using sun altitude, wind speed, diffuse lighting, and wavelength as inputs, the ANN model was able to accurately simulate rho(s), with a low root mean square error of 0.003. A sensitivity analysis with the ANN model indicated that sun altitude and diffuse light had the highest influence on rho(s), contributing to over 82% of predictability of the ANN model. Therefore, the ANN modeling framework can be an accurate tool for estimating surface reflectance in applications that require volume reflectance of water.  相似文献   
60.
The effect of electrolytic chemical concentration on wear-resistance, corrosion-resistance, adhesion and wettability properties of pure nickel and nickel–alumina composite coatings has been investigated in this paper. Coatings were electroplated over steel substrates under constant pulse conditions using pulse electrodeposition technique. Corrosion-resistance results show that the anti-corrosion properties are increasing with medium concentration (MC) both for pure nickel and nickel–alumina composite coating. For anti-wear properties, the MC showed increasing trend in case of pure nickel coatings but decreased in nickel–alumina composite coatings. In composite coating, the higher and low concentrations of electrolyte showed the higher wear resistance properties. Furthermore, the influence of electrolyte concentration on changing surface morphologies, mechanical, wettability and adhesion properties have been investigated and reported here. Surface morphologies of the synthesized coatings were studied with scanning electron microscopy (SEM) and energy-dispersive spectroscopy. Coatings surface mapping and wear analyses were examined by using 3D white light interferometry.  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