Perhaps you should try some spelling variations:
astronomy sergey » astronomy survey, astronomy surveys, astronomy large
moore practical » moocs practical, mouse practical, course practical
astronomy seven » astronomy some, astronomy science, astronomy between
more practical » some 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) OR (more practical)) ((astronomy sergey) OR (astronomy seven)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "the patrick ((moore practical) or (more practical)) ((astronomy sergey) OR (astronomy seven))".
• Adding a wildcard symbol may retrieve word variants: the patrick ((moore practical) or (more practical)) ((astronomy sergey) OR (astronomy seven))*.