Perhaps you should try some spelling variations:
"communicated diseases" » "communicated disease", "communicable diseases", "communicable disease"
"complicated diseases" » "complicated cases", "complex diseases"
"mediated diseases" » "related diseases", "medical diseases", "related disease"
"complicated case" » "complicated cases", "complicated acute", "complicated chapter"

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: (("communicated diseases") OR ((((("complicated diseases") OR ("complicated case"))) OR ("mediated diseases")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"communicated diseases\") or (((((\"complicated diseases\") OR (\"complicated case\"))) or (\"mediated diseases\"))))".
• Removing quotes may allow a broader search: (( communicated diseases ) or ((((( complicated diseases ) OR ( complicated case ))) or ( mediated diseases )))).
• Adding a wildcard symbol may retrieve word variants: (("communicated diseases") or ((((("complicated diseases") OR ("complicated case"))) or ("mediated diseases"))))*.