Perhaps you should try some spelling variations:
"middle plant culture" » "middle explant culture", "middle print culture", "middle explant cultures", "middle plane culture", "middle place culture", "middle part culture"
"middle east culture" » "middle yeast culture", "middle last culture", "middle yeast cultures"
"middle past culture" » "middle last culture", "middle post culture", "middle yeast culture", "middle part culture", "middle phase 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 east culture") OR ((("middle past culture") OR ("middle plant culture")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"middle east culture\") or (((\"middle past culture\") OR (\"middle plant culture\"))))".
• Removing quotes may allow a broader search: (( middle east culture ) or ((( middle past culture ) OR ( middle plant culture )))).
• Adding a wildcard symbol may retrieve word variants: (("middle east culture") or ((("middle past culture") OR ("middle plant culture"))))*.