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   70篇
  免费   2篇
综合类   2篇
化学工业   13篇
机械仪表   5篇
能源动力   1篇
轻工业   15篇
无线电   10篇
一般工业技术   9篇
冶金工业   10篇
自动化技术   7篇
  2021年   2篇
  2020年   2篇
  2019年   6篇
  2018年   3篇
  2017年   5篇
  2016年   1篇
  2013年   7篇
  2011年   5篇
  2010年   1篇
  2009年   1篇
  2006年   5篇
  2005年   2篇
  2004年   2篇
  2003年   4篇
  2000年   1篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1995年   4篇
  1991年   1篇
  1989年   1篇
  1988年   2篇
  1985年   1篇
  1983年   2篇
  1982年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有72条查询结果,搜索用时 15 毫秒
21.
22.
A novel coupling medium for acoustic microscopy is proposed, viz gas under elevated pressures. Using a frequency of 45 MHz in argon at 30 atmospheres, a resolution close to the theoretical limit has been reached. We predict that it should be possible, working at less than 400 atmospheres and at higher frequencies, to achieve a resolution better than 1000 ?.  相似文献   
23.
The literature suggests that the bottom-line changes often cited in lean implementation success stories, such as reduced inventories and faster flow times, are not the only results that should be considered. The potential detrimental effects on employees should be considered as well, or turnover and morale problems may sabotage the effectiveness of such implementations. However, the ways in which lean production environment influence employee behaviour has received scant empirical attention. The aim of this paper is to examine the mediating effect of job involvement on the relationship between perceived organisational support and turnover intention in the lean production in Sri Lanka. A random sample of 616 shop-floor employees engaged full-time in export-apparel manufacturing firms that have implemented a formal lean production system in the whole manufacturing function and it has become the standard of operation for at least 1 year in Sri Lanka responded. Regression analysis was used to test the hypotheses. It was found that job involvement partially mediates the relationship between perceived organisational support and turnover intention. The findings provide useful information to better understand employee perceptions toward lean production environment and the findings will be a source of general guidance in stimulating future research in this area.  相似文献   
24.
1. The role of allopurinol in the protection of kidney function following ischaemia-reperfusion injury has been investigated using the novel technique of near-infrared spectroscopy. 2. An in vivo model of rat kidney ischaemia was used, with the expected falls in blood and tissue oxygenation seen and confirmed by near-infrared spectroscopy. 3. Allopurinol infusion increased the rate of reperfusion of oxygenated blood seen in control rats (P < 0.05). 4. Allopurinol enhanced the rate of tissue oxygenation during early reperfusion (P < 0.01). 5. This study provides further evidence for the proposed benefits of allopurinol in ischaemia-reperfusion injury. Furthermore, the potential of near-infrared spectroscopy as a technique of value in interventional studies of this nature is confirmed.  相似文献   
25.
The Glasgow Coma Scale (GCS) is routinely used in the acute care setting after traumatic brain injury (TBI) to guide decisions in triage, based on its ability to predict morbidity and mortality. Although the GCS has been previously demonstrated to predict mortality, efficacy in prediction of functional outcome has not been established. The purpose of this study was to assess the value of the acute GCS in predicting functional outcome in survivors of TBI. This study used the Multicenter National Institute on Disability and Rehabilitation Research TBI Model Systems database of 501 patients who had received acute medical care and inpatient rehabilitation within a coordinated neurotrauma program for treatment of TBI. Initial and lowest 24 hr GCS scores were correlated with the following outcome measures: the Disability Rating Scale (DRS), Rancho Los Amigos Levels of Cognitive Functioning Scale (LCFS), and cognitive and motor components of the Functional Independence Measure (FIM(SM)-COG and FIM(SM)-M). Outcome data were collected at admission to and discharge from the inpatient TBI rehabilitation unit. Correlation analysis revealed only modest, but statistically significant, relationships between initial and lowest GCS scores and outcome variables. Initial and lowest GCS score comparison with outcome demonstrated the following correlation coefficients: admission DRS, -0.25 and -0.28; discharge DRS, -0.24 and -0.24; admission LCFS, 0.31 and 0.33; discharge LCFS, 0.27 and 0.25; admission FIM-COG, 0.36 and 0.37; discharge FIM-COG, 0.23 and 0.23; admission FIM-M, 0.31 and 0.31; discharge FIM-M, 0.25 and 0.21. The GCS as a single variable may have limited value as a predictor of functional outcome.  相似文献   
26.
27.
Surface-wave holographic techniques can be used to detect the presence of small defects. The detection limit is usually determined not by signal to noise considerations, but rather by the presence of spurious background signals, such as bulk waves. The letter describes a technique for eliminating this background, and demonstrates the improvement in the detection limit.  相似文献   
28.
The objective of the research work was to investigate the use of steam as an alternative fluid for air in spun-like textured yarn manufacturing and to investigate the effect of wetting on texturing performance. An existing air-jet texturing machine was modified to supply either air or steam to the texturing nozzle. Both air-jet and steam-jet textured yarns were made using the same process parameters with and without core-yarn wetting. The effect of core-yarn wetting on the texturing performance has been studied. Results show that core-yarn wetting is critical for air-jet texturing but do not have considerable impact on steam-jet texturing. Therefore, core-yarn wetting could be eliminated in steam-jet texturing. Further, steam-jet texturing shows its capability in manufacturing spun-like textured yarns with better performance than the air-jet. Therefore, it can be concluded that steam can be used as an alternative fluid for air in making spun-like textured yarns without core-yarn wetting.  相似文献   
29.
Electronic Markets -  相似文献   
30.
Although it is recommended to offer free drinking water (called drinking water hereafter) immediately after birth, producers wait, on average, 17 d to first offer drinking water to newborn dairy calves. The objective of this study was to examine water and feed intake, growth performance, health status, and nutrient digestibility of Holstein heifer calves offered drinking water from birth (W0) as compared with those offered it at 17 d of age (W17), when fed an ad libitum volume of milk. Thirty Holstein heifer calves, balanced for parity of the dam, birth weight, and birth week, were randomly assigned (n = 15) to W0 or W17. Calves had free access to drinking water and a starter ration, offered in 2 separate buckets, until they were 70 d of age. Calves were bottle-fed with pasteurized whole milk 3× per day (2.0 kg/feeding until d 14, and 3.2 kg/feeding thereafter). Calves were partially weaned (33% of the milk allowance 1 × per day) at 42 d of age and completely weaned at 49 d of age. Drinking water intake, starter intake, milk intake, ambient temperature, and the fecal consistency were recorded daily. Body weight, hip height, hip width, heart girth, and body length were measured weekly. Blood (drawn from a jugular vein) was analyzed for hematocrit and haptoglobin concentrations at 14 d of age. On d 69 and 70, total fecal output of individual calves was measured and analyzed for chemical composition to determine apparent total-tract digestibility of nutrients. When offered from birth, newborn calves consumed 0.75 ± 0.05 kg/d water aside from the water they received from ad libitum milk allowance during the first 16 d. Once offered, W17 calves drank more water (59%) than W0 calves during the preweaning period. Starter intake of W0 and W17 calves was similar, but W0 calves consumed 0.285 kg/d more milk and tended to achieve greater body weight and heart girth compared with W17 calves during the preweaning period. Offering water from birth versus offering it later did not affect the number of days with diarrhea, intensity of diarrhea, or blood hematocrit and haptoglobin concentrations of preweaned calves. Despite a similar starter intake, W0 calves had greater hip height, body length, apparent total-tract digestibility of acid detergent fiber and neutral detergent fiber, and feed efficiency than W17 calves postweaning (50 to 70 d of age). When followed up to 5 mo of age, W0 calves had greater body weight than W17 calves. Provision of drinking water immediately after birth could improve growth and development of calves pre- and postweaning, potentially by stimulating rumen development, thus increasing nutrient availability.  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