After you find a useful book, scroll down to the "Details" heading to find the book's "Subjects." Here you'll find a list of related subjects that you might consider adding to your search. You can also click on a subject link in the record, e.g. clicking on "Community health services" would bring up a list of all the Library's books, journals, etc. on that topic.
Sometimes browsing the library stacks can help you find books you didn't even know you were looking for. The following are good areas to peruse.
LB3401-3495: School Hygiene, school health services
RA421-790.95: Public Health, Hygiene, Preventive Medicine
RA440-440.87: Public Health, Study and teaching
Maps of the library are available at the 2nd floor Reference Desk, elevator lobbies, and also online.