Search terms, not sentences for academic research
Here is a really good tool to help nail all of that down. Print it out. Check off the search terms from the concept lists as you use them so that you don't end up doing the same work twice.
For help with finding synonyms, mine keywords from class readings or background resources you've already looked at. Look especially for words that uniquely describe the topic. As you begin to find articles, look at the subject descriptors and abstracts for more key words, and check the bibliographies for sources cited.
Good luck with your research!