PubMedEmbaseCochrane LibraryChina National Knowledge InfrastructureWan Fang DatabaseWeb of ScienceChinese Scientific Journal DatabaseChina Biomedical Literature Service SystemCNKIchronic obstructive pulmonary disease+2 more
…gh a variety of electronic databases, including Web of Science, PubMed, Embase, Cochrane Library, China Biomedical Literature Service …