Limiting to Full Text Online in Franklin Articles+ provides access to all full-text resources in the database for which the Penn Libraries has full-text access, as well as open access full-text content.
Limited to Open Access restricts the search results to publications that are accessible to all and and that do not require PennKey authentication.
Note that limiting to full text in some databases, including many EBSCO databases, many actually eliminate many quality full-text results that are available through the Penn Libraries, but not necessarily on that specific platform.
See also: Connecting to Full Text within Franklin Articles+