Perhaps you should try some spelling variations:
communicate diseases » communicable diseases, communicated disease, communicate disabled
communicable disease » communicable diseases
complicated diseases » complicated cases, complex diseases, mediated 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 ((( communicable disease ) OR ( complicated diseases )))).
• Adding a wildcard symbol may retrieve word variants: (( communicate diseases ) or ((( communicable disease ) or ( complicated diseases ))))*.