Perhaps you should try some spelling variations:
astronomy studies » astronomy study, economy studies, astronomy status
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moore practical » more practical, moocs practical, mouse practical

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