Duplicate Cards

I have several subdecks (1 per chapter) underneath one larger deck(for the book) that I am adding vocabulary too. The thing is that the book frequently repeats words in vocabulary lists and I don't always remember whether I have already added a word. Is there a way that I can identify a duplicate card before/after it is created? And I would want to see if it is a duplicate with any cards in the current deck(for this chapter) as well as any in the parent deck (for the book).

There is not duplicate detection at the moment (other than using the search), but I am planning to add duplicate detection in a future update. It will check the primary field of a card, or if the card is not using a template it will compare the first line of the card with other cards in the database.