Perhaps you should try some spelling variations:
astronomy surveys » astronomy survey, astronomy surveying, astronomy survives
some positional » some positions, game positional, some propositional
some position » some positions, home position, same position

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 trick ((some positional) OR (some position)) astronomy surveys.
• Adding a wildcard symbol may retrieve word variants: the trick ((some positional) or (some position)) astronomy surveys*.