Example of full electronic search strategy used for each online database
| Data source | Search strategy | Number of hits | Number of potentially relevant (by title and/or abstract) | Number selected (additional to previous searches) |
|---|---|---|---|---|
| Web of Science (1900 to 1 October 2015) | a. 1 or 2 or 3 | 48 308 | – | – |
| b. a AND (4 or 5 or 6 or 7 or 8 or 9) | 1974 | – | – | |
| c. a AND (10 or 11 or 12) | 683 | – | – | |
| d. b AND (10 or 11 or 12) | 120 | 28 | 25 | |
| e. a AND (13 or 14) | 255 | 45 | 20 | |
| f. b and (13 or 14) | 88 | 10 | 1 | |
| g. c AND (13 or 14) | 80 | 27 | 2 | |
| h. b AND (10 or 11 or 12) AND (13 or 14) | 23 | 8 | 0 | |
| i. c AND (15 or 16) | 110 | 22 | 7 | |
| j. b AND (10 or 11 or 12) AND (15 or 16) | 29 | 9 | 0 | |
| Total | 146 | 55 |
Letters represent each search strategy listed; numbers represent each Medical Subject Heading and text word identified in table 1.