I am not sure why this is not included but the accession number or PMID field should definitely be a choice in preferences for duplicate search. I have spoken to tech support about this and they said they would put it on the list at least 4 updates ago. Their workaround has been to tell me to use the move command to copy the accession number to the label field then choose to include the label field in the duplicate search. By doing this I found 89 duplicates that I did not find any other way!
Until EndNote adds searching for duplicates by PMID or accession number (or DOI as I just requested), that is a decent work around. I am glad you posted. Thanks!
Yes, but it is only a workaround. This is commercial software (not Zotero) so they should be much more responsive. I have been asking fo rthis feature since X3.