Perhaps you should try some spelling variations:
astronomy surveys » astronomy survey, astronomy surveying, astronomy survives
astronomy seven » astronomy some, astronomy science, astronomy between
c practical » 2 practical, 7 practical, 8 practical
patrick c » patrick _, patrick a, patrick d

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: the patrick c practical ((astronomy surveys) OR (astronomy seven)).
• Adding a wildcard symbol may retrieve word variants: the patrick c practical ((astronomy surveys) or (astronomy seven))*.