Perhaps you should try some spelling variations:
experimental clinical » experimental bernal
experimental physical » experimental physics, experimental music
clinical instrument » musical instrument
physical instrument » musical instrument, musical instruments, physical environment

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( experimental clinical instrument ) OR ( experimental physical instrument ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( experimental clinical instrument ) OR ( experimental physical instrument ))".
• Adding a wildcard symbol may retrieve word variants: (( experimental clinical instrument ) OR ( experimental physical instrument ))*.