全文获取类型
收费全文 | 16129篇 |
免费 | 1721篇 |
国内免费 | 1041篇 |
专业分类
电工技术 | 3252篇 |
技术理论 | 1篇 |
综合类 | 2029篇 |
化学工业 | 262篇 |
金属工艺 | 286篇 |
机械仪表 | 1669篇 |
建筑科学 | 1719篇 |
矿业工程 | 565篇 |
能源动力 | 414篇 |
轻工业 | 153篇 |
水利工程 | 476篇 |
石油天然气 | 364篇 |
武器工业 | 564篇 |
无线电 | 2149篇 |
一般工业技术 | 1819篇 |
冶金工业 | 601篇 |
原子能技术 | 147篇 |
自动化技术 | 2421篇 |
出版年
2024年 | 66篇 |
2023年 | 169篇 |
2022年 | 270篇 |
2021年 | 329篇 |
2020年 | 401篇 |
2019年 | 364篇 |
2018年 | 335篇 |
2017年 | 447篇 |
2016年 | 527篇 |
2015年 | 566篇 |
2014年 | 954篇 |
2013年 | 950篇 |
2012年 | 1107篇 |
2011年 | 1252篇 |
2010年 | 905篇 |
2009年 | 976篇 |
2008年 | 966篇 |
2007年 | 1204篇 |
2006年 | 1072篇 |
2005年 | 891篇 |
2004年 | 801篇 |
2003年 | 717篇 |
2002年 | 560篇 |
2001年 | 528篇 |
2000年 | 478篇 |
1999年 | 348篇 |
1998年 | 277篇 |
1997年 | 240篇 |
1996年 | 202篇 |
1995年 | 179篇 |
1994年 | 165篇 |
1993年 | 96篇 |
1992年 | 98篇 |
1991年 | 52篇 |
1990年 | 67篇 |
1989年 | 44篇 |
1988年 | 54篇 |
1987年 | 42篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 19篇 |
1983年 | 20篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1979年 | 6篇 |
1965年 | 9篇 |
1964年 | 11篇 |
1957年 | 9篇 |
1956年 | 9篇 |
1955年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
《Ergonomics》2012,55(4):556-572
Despite the ongoing health problem of repetitive strain injuries, there are few tools currently available for ergonomic applications evaluating cumulative loading that have well-documented evidence of reliability and validity. The purpose of this study was to determine the inter-rater reliability of a posture matching based analysis tool (3DMatch, University of Waterloo) for predicting cumulative and peak spinal loads. A total of 30 food service workers were each videotaped for a 1-h period while performing typical work activities and a single work task was randomly selected from each for analysis by two raters. Inter-rater reliability was determined using intraclass correlation coefficients (ICC) model 2,1 and standard errors of measurement for cumulative and peak spinal and shoulder loading variables across all subjects. Overall, 85.5% of variables had moderate to excellent inter-rater reliability, with ICCs ranging from 0.30–0.99 for all cumulative and peak loading variables. 3DMatch was found to be a reliable ergonomic tool when more than one rater is involved. 相似文献
163.
164.
《Ergonomics》2012,55(10):1266-1277
Workers in physically demanding occupations (PDOs) are frequently subjected to physical selection tests. To avoid legal ramifications, workplaces must be able to show that any personnel selection procedures reflect the inherent requirements of the job. A job task analysis (JTA) is fundamental in determining the work tasks required for employees. To date, there are no published instructions guiding PDO researchers on how to conduct job task analyses. Job task analysis research for non-PDOs offers some insight into the expected reliability and validity of data obtained on the most prevalent task domains in job analysis (importance, frequency, time spent and difficulty). This review critiques such research, and the existing published material on JTA of PDOs, and provides recommendations for future research and practice. Practitioner Summary: There are no published guidelines for physically demanding occupation (PDO) researchers conducting job task analysis (JTA). Given the legal consequences of improperly conducted JTA, scientifically valid instructions for JTA practitioners are required. This review critiques existing research which analyses reliabilities of JTA data, and provides guidelines for PDO researchers conducting JTA. 相似文献
165.
《Ergonomics》2012,55(6):977-991
Objective: to determine the reliability and the concurrent validity of the Spineangel® lumbo-pelvic postural monitoring device. Methods: the dynamic lumbo-pelvic posture of 25 participants was simultaneously monitored by the Spineangel® and FastrakTM devices. Participants performed six different functional tasks in random order. Within-task, within-session and between-day intraclass correlation coefficients (ICC(3,1), ICC(3,5), ICC(2,5), respectively) reliability were calculated for Spineangel® measurements. Concurrent validity of the Spineangel® was assessed by means of a Bland and Altman plot and by means of Pearson's correlation coefficient and paired t-test. Results: within-task, within-session and between-day ICC for the Spineangel® were found to be excellent (>0.93). The Spineangel® and FastrakTM pelvic measurements were found to have a good correlation (R = 0.77). Conclusion: the Spineangel® is a reliable and valid device for monitoring general lumbo-pelvic movements when clipped on the belt or waistband of workers' clothing during various occupational activities. Practitioner summary: The Spineangel® can be used for assessing lumbo-pelvic posture during work or daily-life activities. This device was found to provide reliable and valid measurements for lumbo-pelvic movements. Further research is required to determine whether the use of this device is clinically relevant for patients presenting with low back pain. 相似文献
166.
张薇 《计算机工程与设计》2012,33(3):1140-1144
为解决城市交通路网中容量的随机性对可靠性研究的影响问题,建立了随机流交通路网可靠性模型,提出了一种基于改进粒子群算法的交通路网可靠性评价方法,该方法能够搜索到满足条件的多个解,在算法中引入了一种转移机制可以有效地避免粒子陷入局部无目标搜索状态,又可保证全局搜索能力,最终能够搜索到路网在d需求量下的所有d-下界点以计算路网的可靠性.通过算例结果表明了该改进粒子群算法的可行性及准确性. 相似文献
167.
168.
169.
170.
Errors of pressure measurement are considered. The error as a function of the pressure for a vacuum gauge rated at up to 1000
Pa is calculated as an example. It is 0.15 ≤ δp/p ≤ 0.2% over a pressure range of 14 ≤ p ≤ 1000 Pa and it increases hyperbolically
up to 100% with p = 0.01 Pa. The parametric reliability of the instrument and its immunity to an accidental increase in pressure
the atmospheric level is substantiated.
__________
Translated from Izmeritel’naya Tekhnika, No. 9, pp. 37–41, September, 2006. 相似文献