Hi Jeni,
This is Anne Jung-Mathews, one of the reference librarians at Lamson. I just sent you seven articles that I found, a couple which looked to be precisely the topics you were looking for. With those artices, check the author's references to see what material they consulted in writing the article.
For additional research, I would try a search in Academic Search Premier and ERIC. For best results, search them one at a time.
Use the search term CLASSROOM (also try CLASSROOM RESEARCH) as a SUBJECT search, and combine that with either of your terms like engagement, reading comprehension, and so forth.
If you have trouble finding the databases, just let us know.
Yours sincerely,
Anne Jung-Mathews