Perhaps you should try some spelling variations:
practice state » practice study
practice safe » practice some
practice set » practice self, practice six, practice some
practice so » practice some, practice six, practice self

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: trial ((((practice state) OR (practice safe))) OR (((practice set) OR (practice so)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "trial ((((practice state) OR (practice safe))) or (((practice set) or (practice so))))".
• Adding a wildcard symbol may retrieve word variants: trial ((((practice state) OR (practice safe))) or (((practice set) or (practice so))))*.