Perhaps you should try some spelling variations:
"classical mechanical" » "chemical mechanical", "statistical mechanical", "classical mathematical"
"physical mechanical" » "physico mechanical", "physical mechanisms", "chemical mechanical"
"classical mechanism" » "classical mechanisms", "classical mechanistic", "physical mechanism"
"classical mechanics" » "classical mechanisms"

Try widening your search to All Fields.

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