Possibility of Converting PDF to RIS

I have four PDFs files that each one has roughly 300 abstracts (an abstract inlcudes title, and abstract text). I need to search for duplicated abstracts based on title within each PDF file. Is there any way where I can convert the PDF files to RIS and then upload them to EndNote to look for duplocation?I know this step should have been taken care of before I downloaded the abstracts from the database I used, but now I wonder if it is possible to convert to look for duplicate. 

Other suggestions to look for duplicates that may fulfill my needs are highly welcome and appreiated.