Search of: ozone | COVID - Modify Search
Modify your search using expert search syntax.
Note: The ClinicalTrials.gov search syntax is being updated to match the ClinicalTrials.gov application programming interface (API) search syntax. Documentation and interactive examples of the new syntax can be found on the ClinicalTrials.gov API web site. The current syntax will continue to work, but will not be updated to support new features.
This page last reviewed in January 2020