PMC:7536927 / 3168-3263 JSONTXT

{"project":"LitCovid-PD-CLO","denotations":[{"id":"T14","span":{"begin":71,"end":74},"obj":"http://purl.obolibrary.org/obo/CLO_0051582"}],"text":" have been largely closed for indefinite periods and clinical research has been plagued with co"}