Table A1.
Databases searched for research articles. In brackets is the date of inception of the database. The 2nd column shows the number of search results and the 3rd column the number of search results after removing duplicates.
| DATABASE | Number of Results | Number of Results after Removing Duplicates |
|---|---|---|
| Embase (1971–) | 1292 | 1345 |
| Medline ALL Ovid (1946–) | 723 | 113 |
| Web of Science Core Collection (1975–) | 693 | 55 |
| Cochrane CENTRAL register of trials (1992–) | 21 | 15 |
| Google scholar | 200 | 147 |
| Total | 2929 | 1675 |
Original search strings of the respective databases introduced in Figure 2.