Perhaps you should try some spelling variations:
explant culture » explant cultures
middle explant » middle england, middle plane, riddle explain
plane culture » plant culture, place culture, plate culture
plan culture » plant culture, plant cultures, place culture

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: (( middle ((plane culture) OR (plan culture)) ) OR ( middle explant culture )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( middle ((plane culture) OR (plan culture)) ) or ( middle explant culture ))".
• Adding a wildcard symbol may retrieve word variants: (( middle ((plane culture) OR (plan culture)) ) or ( middle explant culture ))*.