Perhaps you should try some spelling variations:
astronomy surveys » astronomy survey, astronomy surveying, astronomy survives
trials political » trials clinical
astronomy large » astronomy sergey, astronomy line, astronomy long

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 trials political ((astronomy large) OR (astronomy surveys)).
• Adding a wildcard symbol may retrieve word variants: the patrick trials political ((astronomy large) or (astronomy surveys))*.