全文获取类型
收费全文 | 130篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 43篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
能源动力 | 5篇 |
轻工业 | 6篇 |
无线电 | 13篇 |
一般工业技术 | 11篇 |
冶金工业 | 37篇 |
自动化技术 | 12篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有131条查询结果,搜索用时 15 毫秒
11.
One strategy for alleviating excess latency (delay) in the Internet is the caching of web content at multiple locations. This
reduces the number of hops necessary to reach the desired content. This strategy is used for web content such as html pages,
images, streaming video, and Internet radio. The network of servers which store this content, and the collections of objects
stored on each server, is called a content distribution network (CDN). In order to optimally design a CDN, given a network
topology with available server storage capacity at various points in the network, one must decide which object collections
to place on each server in order to achieve performance or cost objectives. The placements must be within the storage limits
of the servers and must reflect the request patterns for each collection of objects to be cached. Researchers have suggested
formulations for the CDN problem which address performance by minimizing latency (the average number of hops is a commonly
accepted measure of latency) from client to content, or formulations that focus on minimizing cost of storage and/or bandwidth.
In this research, we develop a model which allows for the simultaneous treatment of performance and cost, present examples
to illustrate the application of the model and perform a detailed designed experiment to gain insights into cost/hops tradeoff
for a variety of network parameters. 相似文献
12.
M. W. Roberson P. A. Deane S. Bonafede A. Huffman S. Nangalia 《Journal of Electronic Materials》2000,29(10):1274-1277
Soft-errors caused by lead in solder-bumping have been a concern for many years. The problem is of special concern for high-density
interconnection applications requiring solder to be placed directly over active circuitry. In that situation, alpha particles
emitted by radioactive lead cause soft-errors with no possibility of shielding circuitry. For optimal cost-effectiveness,
though, not all solder bumped wafers require low-alpha lead. MCNC has developed a solder bumping facility with both a research
branch at MCNC and a full-scale production facility at its spin-off, Unitive Electronics Inc. We present results here of our
work in incorporating low-alpha lead as part of our solder bumping process. We describe the amount of cross-contamination
measured when alternating plating baths of regular lead and low-alpha lead. 相似文献
13.
Cross R.B.M. De Souza M.M. Deane S.C. Young N.D. 《Electron Devices, IEEE Transactions on》2008,55(5):1109-1115
The performance and stability of thin-film transistors with zinc oxide as the channel layer are investigated using gate bias stress. It is found that the effective channel mobility, ON/OFF ratio, and subthreshold slope of the devices that incorporate SiN are superior to those with SiO2 as the dielectric. The application of positive and negative stress results in the device transfer characteristics shifting in positive and negative directions, respectively. The devices also demonstrate a logarithmic time-dependent threshold voltage shift suggestive of charge trapping within the band gap and the band tails responsible for the deterioration of device parameters. It is postulated that this device instability is partly a consequence of the lattice mismatch at the channel/insulator interface. All stressed devices recover to near-original characteristics after a short period at room temperature without the need for any thermal or bias annealing. 相似文献
14.
The maintenance of adequate oxygen delivery (DO2) and tissue uptake (VO2) has become central dogma in the management of the critically ill. However, these parameters are derived using gas tensions measured in mixed venous blood and may not reflect changes in regional blood flow. Therefore, it has become necessary to provide estimates of blood flow to specific organs and to evaluate the most adequate techniques available. In order to define the best means of assessing blood flow to the lower limb noninvasively in normal subjects, measurements of superficial femoral arterial blood flow using Doppler ultrasound (DU) and strain gauge plethysmography (SGP) were compared in 10 normal volunteers at rest and during exercise. To evaluate the effect of strain gauge positioning, results of measurements made under four different combinations of cuff/strain gauge placement were compared in 15 other volunteers. The correlation of the limb blood flow obtained using the two methods at rest and exercise was 0.57 and 0.62 and the limits of agreement (d +/- 2SD) were 0.40 +/- 2.49 and -0.86 +/- 5.22 ml 100 ml-1 tissue min-1 at rest and on exercise, respectively. Results obtained using SGP were more reproducible (Coef. repeat. 0.45 vs. 0.94 ml 100 ml-1 tissue min-1, for SGP and DU, respectively). The various combinations of cuff/strain gauge positioning showed a tendency to over-read when the latter was placed on the thigh, but were not significantly different (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
15.
Self-report estimates of frequency and duration of computer use are used extensively in research related to computer and information systems acceptance. Despite concerns that self-report estimates are inferior to computer log data there is a paucity of research investigating the relationship between self-report and log data measures of computer use. The present study compared self-report estimates and six months of electronic log data for 62 health care workers using a new Community Services Information System. There were moderate to strong correlations between the self-report and electronic log estimates of frequency and duration of system use. Self-report estimates were relatively accurate in that they were quite similar in magnitude to log data values. The merits of combinations of frequency and duration data (composites) were also assessed. 相似文献
16.
K Mizuguchi CM Deane TL Blundell MS Johnson JP Overington 《Canadian Metallurgical Quarterly》1998,14(7):617-623
MOTIVATION: JOY is a program to annotate protein sequence alignments with three-dimensional (3D) structural features. It was developed to display 3D structural information in a sequence alignment and to help understand the conservation of amino acids in their specific local environments. RESULTS:: The JOY representation now constitutes an essential part of the two databases of protein structure alignments: HOMSTRAD (http://www-cryst.bioc.cam.ac.uk/homstrad ) and CAMPASS (http://www-cryst.bioc.cam.ac. uk/campass). It has also been successfully used for identifying distant evolutionary relationships. AVAILABILITY: The program can be obtained via anonymous ftp from torsa.bioc.cam.ac.uk from the directory /pub/joy/. The address for the JOY server is http://www-cryst.bioc.cam.ac.uk/cgi-bin/joy.cgi. CONTACT: kenji@cryst.bioc.cam.ac.uk 相似文献
17.
Sarah Ann Gallagher Gregory J. McCarthy Deane K. Smith 《Materials Research Bulletin》1977,12(12):1183-1190
A systematic study of the preparation of CsAlSiO4 using various cesium oxide, alumina, and silica sources and a typical set of firing conditions was performed. The objective was to determine effective methods of preparing phase-pure CsAlSiO4. The reaction of Cs2CO3 with metakaolin at 600°C (decomposition and calcining), 850°C (prefiring) and 1050°C (crystallization) produced the only phase-pure CsAlSiO4 obtained by these methods. None of the eighteen sets of starting materials yielded a phase-pure CsAlSiO4 in the 1100°C and 1200°C firings. CsAlSiO4 was determined to be isomorphous with RbAlSiO4 as reported by Klaska and Jarchow (1). CsAlSiO4 is orthorhombic with lattice parameters of . The space group is Pna21, with Z = 4. Single crystals of CsAlSiO4 were grown hydrothermally from a lCs2O:1Al2O3:2SiO2 gel in a 3M CsOH solution. The reaction conditions were 770°C and 11, 700 psi. The crystal habit of CsAlSiO4 is needle-like. 相似文献
18.
In conclusion, no individual student complied with every step of the recommended procedure. In fact, 95% failed to comply with some specific steps that are unique to the AHA standards and that experts consider critical to accurate blood pressure measurement. Response to the questionnaire revealed that factors of logistics and attitudes of others influence student compliance or at least make the situation less conducive to adhering to the AHA standards. An additional interesting finding from the questionnaire was that while students may not have complied entirely with the AHA standards, they believed the procedure to be reasonable and to provide an accurate reading of blood pressure. 相似文献
19.
M Deane C Singer M Lawler S McElwaine K Gomez HG Prentice 《Canadian Metallurgical Quarterly》1998,22(12):1207-1209
A 41-year-old woman received a syngeneic BMT for CLL and subsequently developed acute skin GVHD. Transfusion-related allogeneic GVHD was excluded on the basis of an unchanged HLA type in circulating lymphocytes. Short tandem repeat PCR was used to confirm syngeneicity between donor and recipient. The patient had a personal and family history of autoimmune disease which may have made her particularly susceptible to development of syngeneic GVHD. The distinction between allogeneic and syngeneic or autologous GVHD is important because of therapeutic implications. 相似文献
20.
The present investigation was concerned with the implementation of an information system within a health care setting. A large number of staff required training on a new patient management information system (MIS). The aim of this study was to assess occupational differences on a number of psychological variables associated with MIS success. Computer anxiety was of primary concern due to its relationship to avoidance of computers. A total of 175 questionnaires were distributed, with 103 questionnaires being completed and returned for analysis (61.1%). It was found that clerical/administrative staff had significantly higher self-efficacy regarding computer use and more experience with computers. The nursing group experienced significantly more, computer anxiety, negative attitudes, and negative expectations than the clerical group. Self-efficacy was found to be the best predictor of computer related anxiety. The results have implications for MIS implementation strategies particularly in the areas of training and resource allocation. 相似文献