• I had purchased various history reference books through Salem Press and

they come with a database.  Same with the Lincoln Library (comes with a 
database). 

• We haven't gotten there yet but for the medical resources I plan to point the
  students to the search engine on www.usa.gov and have them search. It includes the
  NIH National Institute of Health, CDC Center for Disease Control and much more.
  There is also lots of great historical info there too via all of the various
  agencies.