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   40篇
  免费   0篇
化学工业   7篇
金属工艺   3篇
机械仪表   7篇
能源动力   5篇
轻工业   1篇
无线电   1篇
一般工业技术   3篇
冶金工业   10篇
自动化技术   3篇
  2024年   1篇
  2021年   1篇
  2014年   1篇
  2012年   1篇
  2011年   3篇
  2010年   3篇
  2009年   2篇
  2007年   3篇
  2006年   1篇
  2005年   1篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1998年   6篇
  1997年   2篇
  1995年   1篇
  1993年   1篇
  1988年   1篇
  1985年   1篇
  1979年   1篇
  1976年   2篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有40条查询结果,搜索用时 15 毫秒
21.
This study assessed the survival of a nationally representative sample of older Canadian men, taking into account common comorbid conditions. Mortality follow-up between 1978 and 1989 was conducted for male participants of the Canada Health Survey who were at least 60 years of age at baseline. The proportional hazards model and life table methods were used to examine survival by comorbidity status. Comorbid conditions examined included history of stroke and/or heart disease, high blood pressure, chronic bronchitis or emphysema, diabetes and smoking status, but excluded cancer because of small numbers. For those subjects aged 80 and older, comorbidity was not a significant predictor of survival. A large portion of men between the ages of 60 and 79, even those with pre-existing comorbid conditions, survived at least 10 years after interview. In a clinical setting, more detailed information on comorbid conditions can be obtained to better estimate long-term survival. Notwithstanding, our findings may have implications for the administration of population-based health interventions (e.g. the use of prostate-specific antigen [PSA] blood tests for the early detection of prostate cancer). In particular, our results suggest that there may be little benefit in restricting access to PSA screening based on survival probability in men under age 80.  相似文献   
22.
The objective of this study was to investigate the fundamental aspects of acrylic resin and zirconia nanoparticle interaction to analyze the optical properties and subsequent changes in refractive index with incremental loading of nanoparticles. Poly(methyl methacrylate) (PMMA) reinforced with zirconia nanoparticles were prepared by dip coating, spin coating and solvent casting techniques. An overall understanding of the polymer nanocomposite film has been achieved using the spectroscopic and morphological studies. The vital aspect of this whole study is to derive a simple yet an efficient nanocomposite film capable of imparting extraordinary optical properties. Within the limitations of this research a very crucial property of the material has been revealed. The RI as well as the optical transparency of the nanocomposite film has been steadily maintained with a significant increase of RI by the magnitude of 0.06 and ~100% light transmittance on incorporation of pure zirconia nanoparticles into PMMA matrix has been achieved. The best technique found was spin coating as it could yield thin films and better transparency and higher refractive index.  相似文献   
23.
In a preliminary survey, 484 alumni of the Massachusetts Mental Health Residency Training Program from 1912 to 1967 were surveyed. Approximately 80% were found to have devoted half or more of their professional time to the nonprivate practice of psychiatry for at least one year. These data suggest that a training program with strong academic traditions might produce a preponderance of publicity of oriented psychiatrists. Since previous surveys have indicated a greater proportion of psychiatric time spent in private practice, we suggest that future surveys of psychiatric manpower need to consider the orientation of residency training programs in order to accurately assess the need for future psychiatric manpower.  相似文献   
24.
A GIS based information management system has been developed to help Urban Malaria Control in India. The basic objective is to develop a model to assist planning and implementation of a suitable control measure. The system can help in: (i) identifying high receptive areas in time and space domain; (ii) identifying risk factors for high receptivity; (iii) monitoring and evaluating control measures. To demonstrate this system, information on 33 parameters and malaria cases has been attached to a digitised map of Dindigul, an urban town in Tamil Nadu. Functionalities of the system and its utility are described in this paper. A GIS based information management system ensures that if a localised spurt of the disease occurs, it can be associated rapidly with a likely cause, a specific vector, and a probable human source, so that appropriate preventive action can be taken to arrest any rising trend.  相似文献   
25.
26.
This paper compares some important parameters obtained in the hydrogen production between the photosynthetic microorganisms Spirulina maxima 2342 and Scenedesmus obliquus 39. It is also reported the employment of hydrogen produced in this study (m3 s?1) in a proton exchange membrane fuel cell (PEMFC) for electricity production. A comparison is also made between the electric current generated and the final dry biomass (mA mg?1) under specific experimental conditions. In this study, the electric current generated in the PEMFC for a period of 200 min under the light intensity of 150 µE m?2 s?1 and agitation was monitored. With the average current generated by the fuel cell the hydrogen produced by each microorganism is determined. The chromatography method was used to confirm the presence of hydrogen produced by each microorganism which was fed to the PEMFC. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
27.
The thermo‐oxidative stability of a linear perfluoropolyalkylether fluid has been improved by stressing the fluid at 371°C while bubbling air or nitrogen in an overboard configuration. It is believed that the minor amounts of less stable species present in the fluid, possibly hydrogen‐containing species, are degraded and removed during the process leaving the residual fluid with enhanced stability. Two antioxidation/corrosion additives, a substituted triphenyl phosphine and a substituted diphenyl ether, were formulated with the stressed fluid, and their behavior was compared with the same formulations in unstressed fluid. While the phosphine formulation in stressed fluid showed better stability than its formulation in unstressed fluid, no such effect was noticed with the diphenyl ether additive formulations. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
28.
The thioglucosides (which are precursors of toxic principles) and the fibrous hulls of rapeseed are the two major factors which limit the utilization of rapeseed meal as a protein supplement in human foods. In commercial practice the enzyme responsible for the liberation of toxic principles from thioglucosides is destroyed by a dry-heat treatment, but no attempt is made to remove the thioglucosides or the fibrous matter from the meal. The new wet-heat method of processing to inactivate myrosinase also results in the production of an improved quality of oil. In this paper the advantages of a wet-heat treatment in processing rapeseed are discussed.  相似文献   
29.
30.
A lubrication scheme for MEMS electrostatic lateral output motors based on a mixture of bound and mobile lubricant was studied. Lubrication by bound monolayer alone provided some increase in operational life, but after a short time, the film wore away and the device failed in the unlubricated mode. A mobile phase was used to provide lubricant replenishment. Tribological studies were conducted on Si(100) wafers, as well as on MEMS electrostatic lateral output motors, dip-coated with a mixture of bound and mobile phases of Fomblin Zdol. Accelerated screening tests on Si(100) wafers were undertaken using a pin on disk tribometer. However, the optimum balance of bound and mobile phases was determined by studies on the device itself. The fractional surface coverage of lubricant and the ratio of bound to mobile phase was varied through selection of reaction temperature and rinse chemistry. The mobile phase on model surfaces and devices acted as a source of lubricant replenishment, and together with the bound phase provided dramatic improvement in performance. The wide variation seen in the performance of individual devices suggests that dip coating does not provide a uniform coating on the contacting surfaces of these devices.  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