PT -期刊文章AU -约翰逊,米里亚姆j . AU -Ekström, Magnus AU - Currow, David C. TI - Observational studies and “the eye of the beholder” AID - 10.1183/13993003.01637-2020 DP - 2020 Jul 01 TA - European Respiratory Journal PG - 2001637 VI - 56 IP - 1 4099 - //www.qdcxjkg.com/content/56/1/2001637.short 4100 - //www.qdcxjkg.com/content/56/1/2001637.full SO - Eur Respir J2020 Jul 01; 56