首页 | 官方网站   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   91篇
  免费   7篇
  国内免费   1篇
工业技术   99篇
  2022年   1篇
  2021年   10篇
  2020年   2篇
  2019年   4篇
  2017年   2篇
  2016年   6篇
  2015年   4篇
  2014年   2篇
  2013年   5篇
  2012年   2篇
  2011年   6篇
  2010年   10篇
  2009年   11篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2003年   3篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1992年   1篇
  1989年   1篇
  1985年   2篇
  1984年   5篇
  1983年   2篇
  1982年   1篇
  1980年   1篇
  1972年   1篇
排序方式: 共有99条查询结果,搜索用时 15 毫秒
1.
2.
Data mining methods have been successfully applied to different fields. Aviation industry is one of them. There is a large amount of knowledge and data accumulation in aviation industry. These data could be stored in the form of pilot reports, maintenance reports, incident reports or delay reports. This paper explains the data mining application on the incident reports of the Federal Aviation Administration (FAA) Accident/Incident Data System database, contains incident data records for all categories of civil aviation between the years of 2000 and 2006. In this study, we applied data mining methods on the incident reports. Moreover rough sets concept is used to reduce the attributes of data set. The purpose of this application is to find out the effective attributes in order to reduce the number of the fatality in the incidents. The categorization tools and decision trees are used to find the relations and rules about the incidents resulted in fatality. For this purpose data-mining analysis is conducted. As a result some rules about the fatality are obtained and also the parameters that affect the fatality in the incident have determined. The rules found are tested in terms of their accuracy and reliability, and these results are seen to be meaningful.  相似文献   
3.
4.
5.
Hydrous ruthenium oxide/activated carbon black (RuOx/ACB) composite was synthesized for the first time for supercapacitors by a chemical impregnation method. The RuOx/ACB composite is characterized by thermogravimetric analysis (TGA), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The results of TGA and TEM characterization showed that the reaction temperature of composite moved to lower temperature due to the catalytic effect of RuOx. XRD characterization of RuOx/AC illustrated that amorphous hydrous RuOx structure maintained in the composite heated at 150 °C. The equivalent series resistance (ESR) of the composite almost increased with the increase of RuOx content in the composite. The specific capacitance (Csp) of the composite increased with increasing RuOx content in the composite while the Csp of RuOx decreased from 1255.8 to 533.7 F g?1. The above results showed that the utilization of RuOx decreased with higher loading RuOx on ACB.  相似文献   
6.
Phosphatidylcholine is a major component of biological membranes and is an important mediator of physiological functions in mammals. In addition to biosynthetic routes of availability, phosphatidylcholine is also derived from the diet. The levels of phosphatidylcholine are quite low in fruits and fruit products. As the fruits ripen, the phospholipids are degraded into neutral lipids causing a drastic decline in phospholipid content. In the present study, we have evaluated the effects of external supplementation of soy lecithin on physico-chemical properties of tomato juice and sauce, as well as grape juice. The levels of protein, soluble solids and ash content were significantly enhanced by the addition of lecithin. The bulk viscosity of tomato juice and the sauce preparation was also enhanced by addition of lecithin. The yellow color values of the juice and sauce preparations were enhanced by lecithin. In grape juice preparations, the addition of lecithin did not cause any negative effects, but enhanced the solids content of the juice. Juice preparations with added lecithin were more stable than the controls. Lecithin may form complexes with pectin, lipids and other carbohydrates, affecting the food property and stability by various mechanisms.  相似文献   
7.
Photopolymerization of multifunctional acrylates with 2-thioxanthone-thioacetic acid (TXSCH2COOH) and 2-(carboxymethoxy) thioxanthone (TXOCH2COOH) as the one-component photoinitiator has been investigated by real-time Fourier transform infrared (RT-FTIR) spectroscopy. The photobleaching of these one-component nature initiators was performed in air. The irradiation time for total bleaching was 240 s for TXSCH2COOH and 540 s for TXOCH2COOH.  相似文献   
8.
Reports and news on failure due to corrosion degradation of structures in aggressive environments are common occurrences in literature nowadays. This paper presents deterioration pattern of concrete structures in a coastal environment and effects chloride concentration on the steel reinforcements in concrete as a way towards failure control: water samples were collected from coastal environments (Tin Can Island and Bar Beach, Lagos, Nigeria). Laboratory analyses were carried out to determine the chloride contents and values obtained for the chloride concentrations were used to prepare different concentrations of chloride solutions to be used as aggressive curing environments. The test blocks were connected in parallel to a D.C rectifier set at 10 V to accentuate the rate of corrosion. A Half-Cell potential apparatus was used to determine the corrosion potential at intervals of 4 days for a period of 28 days after the initial 28 days of curing. A simple statistical model that relates chloride concentrations to the strength of the concretes was developed and tested. The study revealed that chloride concentration has significant effect on reinforcement. Rebar in 24878.80 mg/L curing tank was the most affected by corrosion with potential reading of 466.50 mV and the rebar in this block was not able to sustain any tensile load. The model developed described the strength of the concretes with correlation coefficient R 2 higher than 0.950 (R 2 > 0.950).  相似文献   
9.
OBJECTIVE: A quantitative measure of wrist position sense was developed to advance clinical measurement of proprioceptive limb sensibility after stroke. Test-retest reliability, normative standards, and ability to discriminate impaired and unimpaired performance were investigated. DESIGN: Retest reliability was assessed over three sessions, and a matched-pairs study compared stroke and unimpaired subjects. Both wrists were tested, in counterbalanced order. SETTING: Patients were tested in hospital-based rehabilitation units. PATIENTS AND OTHER PARTICIPANTS: Reliability was investigated on a consecutive sample of 35 adult stroke patients with a range of proprioceptive discrimination abilities and no evidence of neglect. A consecutive sample of 50 stroke patients and convenience sample of 50 healthy volunteers, matched for age, sex, and hand dominance, were tested in the normative-discriminative study. Age and sex were representative of the adult stroke population. MAIN OUTCOME MEASURES: The test required matching of imposed wrist positions using a pointer aligned with the axis of movement and a protractor scale. RESULTS: The test was reliable (r = .88 and .92) and observed changes of 8 degrees can be interpreted, with 95% confidence, as genuine. Scores of healthy volunteers ranged from 3.1 degrees to 10.9 degrees average error. The criterion of impairment was conservatively defined as 11 degrees (+/-4.8 degrees) average error. Impaired and unimpaired performance were well differentiated. CONCLUSIONS: Clinicians can confidently and quantitatively sample one aspect of proprioceptive sensibility in stroke patients using the wrist position sense test. Development of tests on other joints using the present approach is supported by our findings.  相似文献   
10.
Laminated fillet blocks made from blue whiting (Micromesistius poutassou) caught in February and April were assessed for quality. The total protein nitrogen value in February-caught fish was greater than the April-caught fish. The bone content, water content and pH values were consistently lower in the February fish than the April fish. Measurement of the acceptability of deep fried, breaded fingers made from the fish and compared with cod fingers produced from fish caught at the same time of year showed a consistent difference between the cod and blue whiting. In addition, the fish fingers from fish caught in February scored consistently higher than those caught in April. The implications of the findings are discussed.  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-23

京公网安备 11010802026262号