Sometimes the starting keyword(s) is/are [or seem] clear (as with a specific animal or disease), but sometimes there's an intermediate step of figuring out which words to start with (as with Dr. Wielgus' group's pregnancy topics). And sometimes it's necessary to step back --to discover and then search a more general term. In any case, as you read what you find, you'll have more terms to integrate into your understanding of the subject you've chosen.We need to spend some time talking about general strategies, and might as well start with books. Here are some Annie search hints.
Find one, then find more using the information in the one
(bibliographies, authors, terminology to add to 'cloud'); the one is, after all, part of an ongoing conversation. You're trying to pick up enough to join that conversation.