时间 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 |
文献量 | 38 | 0 | 1 | 0 | 2 | 0 | 0 | 1 | 0 |
百分比 | 82.61 | 0 | 2.17 | 0 | 4.35 | 0 | 0 | 2.17 | 0 |