Perhaps you should try some spelling variations:
"theoretical geophysics" » "theoretical physics", "theoretical astrophysics", "theoretical topics"
"theoretical physicist" » "theoretical physicists", "theoretical physics", "theoretical basics"
"theoretical mechanics" » "theoretical semantics", "theoretical techniques", "theoretical physics"

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: (("theoretical physicist") OR ((("theoretical geophysics") OR ("theoretical mechanics")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"theoretical physicist\") or (((\"theoretical geophysics\") OR (\"theoretical mechanics\"))))".
• Removing quotes may allow a broader search: (( theoretical physicist ) or ((( theoretical geophysics ) OR ( theoretical mechanics )))).
• Adding a wildcard symbol may retrieve word variants: (("theoretical physicist") or ((("theoretical geophysics") OR ("theoretical mechanics"))))*.