Perhaps you should try some spelling variations:
practical astronomy » optical astronomy, positional astronomy
astronomy sergey » astronomy surveys, astronomy large, astronomy society
astronomy survey » astronomy surveys, autonomy survey, astronomy surveying
drops practical » aris practical, devops practices, arrays practical
astronomy seven » astronomy some, astronomy science, astronomy between
patrick drops » patrick debois, patrick dr, patrick brown
nos nautical » logs nautical, hoc nautical, some nautical
patrick nos » patrick nomo, patrick bas, patrick n

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 drops practical astronomy sergey ) OR ((( the patrick nos nautical astronomy survey ) OR ( the patrick nos nautical astronomy seven )))).
• Adding a wildcard symbol may retrieve word variants: (( the patrick drops practical astronomy sergey ) or ((( the patrick nos nautical astronomy survey ) or ( the patrick nos nautical astronomy seven ))))*.