Perhaps you should try some spelling variations:
"botanical experiment" » "biological experiment", "statical experiments", "botanical specimens"
"animal experiment" » "initial experiments", "natural experiment", "animal experimentation"
"animal experiments" » "initial experimentss", "natural experiments", "animal experimentations", "animal experimental"

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: (("botanical experiment") OR ((("animal experiment") OR ("animal experiments")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"botanical experiment\") or (((\"animal experiment\") OR (\"animal experiments\"))))".
• Removing quotes may allow a broader search: (( botanical experiment ) or ((( animal experiment ) OR ( animal experiments )))).
• Adding a wildcard symbol may retrieve word variants: (("botanical experiment") or ((("animal experiment") OR ("animal experiments"))))*.