Perhaps you should try some spelling variations:
astronomy surveys » astronomy survey, astronomy surveying, astronomy survives
trials political » trials clinical
astronomy sergey » astronomy survey, astronomy large, astronomy society
astronomy seven » astronomy some, astronomy science, astronomy between

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 sergey) OR (astronomy seven))) OR (astronomy surveys)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "the patrick trials political ((((astronomy sergey) OR (astronomy seven))) or (astronomy surveys))".
• Adding a wildcard symbol may retrieve word variants: the patrick trials political ((((astronomy sergey) OR (astronomy seven))) or (astronomy surveys))*.