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   111篇
  免费   11篇
  国内免费   1篇
电工技术   4篇
化学工业   26篇
金属工艺   7篇
机械仪表   4篇
能源动力   1篇
轻工业   4篇
水利工程   2篇
无线电   8篇
一般工业技术   20篇
冶金工业   40篇
原子能技术   2篇
自动化技术   5篇
  2024年   1篇
  2023年   1篇
  2021年   3篇
  2020年   1篇
  2019年   2篇
  2018年   4篇
  2017年   7篇
  2016年   1篇
  2015年   3篇
  2014年   4篇
  2013年   6篇
  2012年   3篇
  2011年   5篇
  2010年   5篇
  2009年   5篇
  2008年   4篇
  2007年   1篇
  2006年   7篇
  2005年   2篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
  1998年   10篇
  1997年   10篇
  1996年   1篇
  1995年   6篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   4篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1979年   2篇
  1976年   2篇
  1972年   2篇
  1970年   2篇
  1956年   1篇
  1955年   1篇
排序方式: 共有123条查询结果,搜索用时 15 毫秒
1.
To establish the relationships among T and B cell responses, active infection, and clinical manifestations in lymphatic filariasis, filarial-specific lymphocyte proliferation, IgG antibody isotypes, and IgE levels were determined in an exposed population: 31 asymptomatic amicrofilaremics, 43 microfilaremics, 12 symptomatic amicrofilaremics, and 52 elephantiasis patients. Lymphocyte proliferation was higher in elephantiasis patients and asymptomatic amicrofilaremics than in microfilaremics (P < .004). A proportion of asymptomatic amicrofilaremics (32%), elephantiasis patients (37%), and symptomatic amicrofilaremics (58%) showed antigen-specific lymphocyte unresponsiveness, and lymphocyte proliferation to filarial antigens correlated negatively with specific IgG4 levels (rho = -0.315, P < .001). As elevated specific IgG4 is an indicator of active infection, it is argued that active infection may result in lymphocyte hyporesponsiveness irrespective of clinical category. Of those with elevated specific IgE levels and high T cell proliferative responses, 70% had elephantiasis, suggesting these factors have a role in pathology. However, the existence of a proportion of elephantiasis patients with low anti-filarial IgE and T cell unresponsiveness to filarial antigens suggests that elephantiasis can be caused by distinct processes.  相似文献   
2.
3.
Mobile sensing and mapping applications are becoming more prevalent because sensing hardware is becoming more portable and more affordable. However, most of the hardware uses small numbers of fixed sensors that report and share multiple sets of environmental data which raises privacy concerns. Instead, these systems can be decentralized and managed by individuals in their public and private spaces. This paper describes a robust system called MobGeoSens which enables individuals to monitor their local environment (e.g. pollution and temperature) and their private spaces (e.g. activities and health) by using mobile phones in their day to day life. The MobGeoSen is a combination of software components that facilitates the phone’s internal sensing devices (e.g. microphone and camera) and external wireless sensors (e.g. data loggers and GPS receivers) for data collection. It also adds a new dimension of spatial localization to the data collection process and provides the user with both textual and spatial cartographic displays. While collecting the data, individuals can interactively add annotations and photos which are automatically added and integrated in the visualization file/log. This makes it easy to visualize the data, photos and annotations on a spatial and temporal visualization tool. In addition, the paper will present ways in which mobile phones can be used as noise sensors using an on-device microphone. Finally, we present our experiences with school children using the above mentioned system to measure their exposure to environmental pollution.
Adrain WoolardEmail:
  相似文献   
4.
A new instrument, density monitor (DENSMO), for aerosol particle size distribution characterization and monitoring has been developed. DENSMO is operationally simple and capable of measuring the effective density as well as the aerodynamic and the mobility median diameters with a time resolution of 1 s, from unimodal particle size distributions. The characterization is performed with a zeroth order mobility analyzer in series with a low pressure impactor and a filter stage. The operation of DENSMO was investigated with sensitivity analysis and, based on the results, optimal operation parameters were determined. DENSMO was also compared, in lab test measurements, against a reference method with several particle materials with bulk densities from 0.92 to 10.5 g/cm3. The results show that the deviation from the reference method was less than 25% for suitable materials.

Copyright © 2016 American Association for Aerosol Research  相似文献   

5.
The changing scene in steel   总被引:1,自引:0,他引:1  
In the past thirty years the United States has moved from a position where it dominated world steel production to where it is now only one of the major world steel producers. The interplay of technology, economics and world politics which has brought this about will be reviewed, with particular emphasis on important technological changes which have occurred in the last three decades. To illustrate how research, development and application interacted to bring about change, specific examples will be given in ore reduction, continuous casting and high-strength steel products. The Edward DeMille Campbell Memorial Lecture was established in 1926 as an annual lecture in memory of and in recognition of the outstanding scientific contributions to the metallurgical profession by a distinguished educator who was blind for all but two years of his professional life. It recognizes demonstrated ability in metallurgical science and engineering. H. W. PAXTON is Vice President-Research of the United States Steel Corporation. He received a B.Sc. and M.Sc. in 1947 and 1948 from the University of Manchester and his Ph.D. in 1952 from the University of Birmingham. In 1953 he became Assistant Professor of Metallurgical Engineering at Carnegie Institute of Technology, subsequently Carnegie-Mellon University, and became Head of the Department of Metallurgy and Materials Science and Director of the Metals Research Laboratory of Carnegie-Mellon in 1966. He was Visiting Professor in Metallurgy and Materials Science at Imperial College, London, in 1962–63 and at the Massachusetts Institute of Technology in 1970, and served two years as the first Director, Division of Materials Research, National Science Foundation 1971–1973. He was a consultant to industry from 1953 to 1974 and has authored many technical papers, primarily in the field of physical metallurgy. He also co-authored a book,Alloying Elements in Steel, with the late Dr. E. C. Bain. Dr. Paxton received the Bradley Stoughton Award for young teachers of metallurgy in 1960. He is a member of the American Association for the Advancement of Science, Directors of Industrial Research, and the Industrial Research Institute; Fellow of the American Society for Metals and The Metallurgical Society of AIME; Past President of TMS; Vice President of the American Institute of Mining Metallurgical, and Petroleum Engineers; Past Chairman of the General Research committee of the American Iron and Steel Institute, and was elected to membership of the National Academy of Engineering on April 3, 1978.  相似文献   
6.
7.
Over the last fifteen years an extensive programme of work on quantifying and predicting creep behaviour of particleboard has been undertaken. This paper first sets out some of the philosophy underlying the selection of test methodology used, and then proceeds to summarise and highlight the principal results obtained under both steady- and unsteady-state environments. Very strong interactions were found in the analysis of variable influencing creep behaviour. The reasons for adopting rheological models as predictive tools are discussed and the merits of a 5-parameter model are illustrated. A 4-parameter model is used to obtain the relative proportions of the three components of creep deflection under different conditions: this procedure clearly demonstrates the significant role of the viscous component in determining creep deflection at high levels of stress and relative humidity.  相似文献   
8.
Magnetic and electrical properties of thermoplastic ceramic-polymer 0–3 composites with Z-type hexaferrite, and MnZn ferrite inclusions were investigated. The complex permeability and permittivity were measured up to 1 GHz where maximum values of ɛ′r=30.47 and μ′r=4.32 and ɛ′r=10.95 and μ′r=1.80 were obtained for MnZn-ER182 and Co2Z-ER182 composites with ∼44.7 vol% and 43.0 vol% filler loadings, respectively. MnZn and Co2Z composites exhibit miniaturization factors as low as 0.09 and 0.23, together with reduced magnetic losses and frequency dispersion. The results indicate that the composites offer novel possibilities for wider feasible frequency bandwidth and adjustable impedance matching and magnetic and dielectric properties.  相似文献   
9.
10.
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