Impact factor and articles submitted by category
| 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | |
| Impact factor | 1.56 | 2.31 | 2.86 | 3.44 | 3.98 | |
| Original research | ||||||
| Full papers | 415 | 411 | 398 | 453 | 505 | 573 |
| Short papers | 51 | 40 | 31 | 36 | 34 | 36 |
| Rapid communications | 5 | 5 | 7 | 3 | 6 | 9 |
| Case reports | 247 | 212 | 211 | 149 | 165 | 186 |
| Editorials/reviews | 38 | 53 | 81 | 57 | 56 | 55 |
| Review series | 31 | 26 | 13 | 19 | 14 | 15 |
| Supplement articles | 41 | 29 | 17 | 16 | 46 | 5 |
| Case report commentaries | 11 | 7 | 7 | 0 | 0 | 0 |
| Letters | 50 | 55 | 72 | 9 | 96 | 95 |
| Total | 889 | 838 | 837 | 812 | 922 | 974 |