Perhaps you should try some spelling variations:
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moocs positional » holds positional, blocks positionals, images positional
moore nautical » board nautical, mile nautical, moore national
patrick moocs » patrick mons, patrick moyes, patrick moore's

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 moocs positional astronomy sergey ) OR ( the patrick moore nautical astronomy sergey )).
• Adding a wildcard symbol may retrieve word variants: (( the patrick moocs positional astronomy sergey ) or ( the patrick moore nautical astronomy sergey ))*.