收费全文 | 263篇 |
免费 | 34篇 |
国内免费 | 46篇 |
安全科学 | 59篇 |
废物处理 | 15篇 |
环保管理 | 32篇 |
综合类 | 167篇 |
基础理论 | 13篇 |
污染及防治 | 34篇 |
评价与监测 | 5篇 |
社会与环境 | 6篇 |
灾害及防治 | 12篇 |
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 15篇 |
2021年 | 17篇 |
2020年 | 13篇 |
2019年 | 12篇 |
2018年 | 20篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 21篇 |
2013年 | 23篇 |
2012年 | 23篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 13篇 |
2008年 | 9篇 |
2007年 | 7篇 |
2006年 | 16篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1973年 | 1篇 |
Methods: Using a head impact machine and a Hybrid III headform, tests were conducted on a rigid steel plate in a number of different configurations and velocities to assess helmet shell and padding performance, to evaluate different vehicle roof padding materials, and to determine the relative injury mitigating contributions of both the helmet and the roof padding. The resultant translational head acceleration was measured and the head injury criterion (HIC) was calculated for each impact.
Results: For impacts with a helmeted headform hitting the steel plate only, which represented a common scenario in an underbelly blast event, velocities of ≤6 m/s resulted in HIC values below the FMVSS 201U threshold of 1,000, and a velocity of 7 m/s resulted in HIC values well over the threshold. Roof padding was found to reduce the peak translational head acceleration and the HIC, with rigid IMPAXX foams performing better than semirigid ethylene vinyl acetate (EVA) foam. However, the head injury potential was reduced considerably more by wearing a helmet than by the addition of roof padding.
Conclusions: The results of this study provide initial quantitative findings that provide a better understanding of helmet–roof interactions in vertical impacts and the contributions of the military helmet and roof padding to mitigating head injury potential. Findings from this study will be used to inform further testing with the future aim of developing a new minimum head clearance standard for occupants of light armored vehicles. 相似文献