分面浏览：Issued Date |
| 当前检索式 | ((ALL：Hardness)) |
| 限定条件 | 无 |
共38条，第1-38条
| 2024 8 | 2023 51 | 2022 155 |
| 2021 199 | 2020 265 | 2019 212 |
| 2018 283 | 2017 275 | 2016 159 |
| 2015 139 | 2014 142 | 2013 119 |
| 2012 139 | 2011 140 | 2010 119 |
| 2009 113 | 2008 123 | 2007 138 |
| 2006 94 | 2005 98 | 2004 72 |
| 2003 59 | 2002 67 | 2001 38 |
| 2000 28 | 1999 17 | 1998 23 |
| 1997 11 | 1996 8 | 1995 11 |
| 1994 5 | 1993 10 | 1992 6 |
| 1991 2 | 1990 2 | 1989 3 |
| 1983 1 | 1905 5 |