Unfortunately, it is not possible at this time to export citations from ClinicalKey into bibliographic management software like EndNote.
How to work around this flaw:
For journal citations, search for these citations in Scopus. Scopus is primarily a journal citation database. You can use the Direct Export option within Scopus to easily send your search results into your EndNote account. To learn more about this option, see the Library's guide to Scopus
For books, you can download a .RIS file to import into EndNote from the library discovery system.