Non-English language articles
| SearchNo. | Most recent query | Resultsn |
| 8 | Search: No. 6 NOT No. 7; limits: publication date 1990–2004 | 978 |
| 7 | Search: English language; limits: publication date 1990–2004 | 6166153 |
| 6 | Search: No. 4 AND No. 5; limits: publication date 1990–2004 | 5265 |
| 5 | Search: No. 1 OR No. 2 OR No. 3; limits: publication date 1990–2004 | 30682 |
| 4 | Search: epidemiology OR prevalence OR incidence; limits: publication date 1990–2004 | 727562 |
| 3 | Search: emphysema OR airway obstruction; limits: publication date 1990–2004 | 17177 |
| 2 | Search: bronchitis chronic OR bronchitis, chronic OR chronic bronchitis; limits: publication date 1990–2004 | 3050 |
| 1 | Search: pulmonary disease, chronic obstructive OR pulmonary disease chronic obstructive OR chronic obstructive pulmonary disease OR COPD; field: all fields; limits: publication date 1990–2004 | 15158 |
COPD: chronic obstructive pulmonary disease.