You can do this in the Vocabulary section using the filters before you start your review session. Why do you need to not show phrases by the way? As long as you are saving phrases that are recurring chunks that appear regularly, they are just as important as learning words. To exclude words or phrases otherwise, you would have to tag the vocabulary you want to review and then filter that list before starting a review session.

It would be helpful if you described what and where in the app you are doing this review.