English language articles
| SearchNo. | Most recent query | Resultsn |
| 6 | Search: No. 4 AND No. 5; limits: publication date 1990–2004, English | 4486 |
| 5 | Search: No. 1 OR No. 2 OR No. 3; limits: publication date 1990–2004, English | 24963 |
| 4 | Search: epidemiology OR prevalence OR incidence; limits: publication date 1990–2004, English | 635624 |
| 3 | Search: emphysema OR airway obstruction; limits: publication date 1990–2004, English | 14171 |
| 2 | Search: bronchitis chronic OR bronchitis, chronic OR chronic bronchitis; limits: publication date 1990–2004, English | 2025 |
| 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, English | 12331 |
COPD: chronic obstructive pulmonary disease.