So what do you do if you feel like nothing is out there? Your searches are getting you 0 results!
This might be because the words you are using to search are too specific and narrow-- or that you are looking for one perfect source that might not exist.
Remember, you are trying to find sources that help you to explain some aspect of your topic, not the one source that answers your question or proves your thesis. That's your job! You have a particular perspective, and your sources are there to provide support, not to steal the show!