Table 2.
Document type during the overall period and per year.
| Type of document | Overall time period: 2020-2021, n | 2020, n | 2021, n |
| Case report | 3294 | 2211 | 1083 |
| Classical article | 2 | 0 | 2 |
| Clinical conference | 7 | 5 | 2 |
| Clinical study | 2 | 2 | 0 |
| Clinical trial | 13 | 7 | 6 |
| Clinical trial protocol | 41 | 39 | 2 |
| Clinical trial, phase II | 1 | 1 | 0 |
| Comparative study | 69 | 58 | 11 |
| Congress | 8 | 5 | 3 |
| Consensus development conference | 5 | 4 | 1 |
| Editorial | 5766 | 4622 | 1144 |
| English abstract | 1664 | 1174 | 490 |
| Equivalence trial | 1 | 0 | 1 |
| Evaluation study | 14 | 11 | 3 |
| Guideline | 15 | 15 | 0 |
| Historical article | 22 | 21 | 1 |
| Interview | 32 | 27 | 5 |
| Introductory journal article | 6 | 6 | 0 |
| Journal article | 88,374 | 58,601 | 29,773 |
| Lecture | 2 | 2 | 0 |
| Preprint or letter | 16,405 | 13,068 | 3337 |
| Meta-analysis | 9 | 5 | 4 |
| Published erratum | 492 | 270 | 222 |
| Retraction of publication | 15 | 7 | 8 |
| Review | 1 | 1 | 0 |
| Systematic review | 120 | 65 | 55 |