Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy, positional astronomy
astronomy survey » astronomy surveys, astronomy sergey, autonomy survey
astronomy study » astronomy studies, astronomy south, astronomy star
mayen practical » man practical, modern practical, seven practical
mics practical » ics practical, micro practical, moocs practical
patrick mayen » patrick bayer, patrick madan, patrick moyes
patrick mics » patrick mons, patrick michel, patrick maill

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 mics practical astronomy study ) OR ( the patrick mayen practical astronomy survey )).
• Adding a wildcard symbol may retrieve word variants: (( the patrick mics practical astronomy study ) or ( the patrick mayen practical astronomy survey ))*.