Perhaps you should try some spelling variations:
communicate diseases » communicable diseases, communicated disease, communicate disabled
complicated diseases » complex diseases, mediated diseases, complicated case
communicable disease » communicable diseases

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((( communicate diseases ) OR ((( complicated diseases ) OR ( complicated cases ))))) OR ( communicable disease )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( communicate diseases ) or ((( complicated diseases ) OR ( complicated cases ))))) or ( communicable disease ))".
• Adding a wildcard symbol may retrieve word variants: (((( communicate diseases ) or ((( complicated diseases ) OR ( complicated cases ))))) or ( communicable disease ))*.