Perhaps you should try some spelling variations:
"theoretical geophysics" » "theoretical astrophysics", "theoretical topics", "theoretical physicist"
"theoretical mechanics" » "theoretical semantics", "theoretical techniques", "theoretical methods"
"theoretical physics" » "mathematical physics", "theoretical analysis"
"theoretical basics" » "theoretical basis", "theoretical bases", "theoretical bisacsh"

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