Perhaps you should try some spelling variations:
"mediated diseases" » "related diseases", "medical diseases", "related disease"
"complicated case" » "complicated acute", "complicated chapter", "complicated grief"
"complicated cases" » "complicated acutes", "complicated chapters", "complicated griefs"

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