Perhaps you should try some spelling variations:
"general preoperative" » "general postoperative", "after preoperative", "therapy preoperative"
"general operative" » "general operation", "general operating", "general comparative"
"general relations" » "general regulations", "general reflections", "general equations"
"general relativity" » "general relatively"

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: (("general relativity") OR ((((("general operative") OR ("general preoperative"))) OR ("general relations")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"general relativity\") or (((((\"general operative\") OR (\"general preoperative\"))) or (\"general relations\"))))".
• Removing quotes may allow a broader search: (( general relativity ) or ((((( general operative ) OR ( general preoperative ))) or ( general relations )))).
• Adding a wildcard symbol may retrieve word variants: (("general relativity") or ((((("general operative") OR ("general preoperative"))) or ("general relations"))))*.