Perhaps you should try some spelling variations:
giao nguoi » gian nguoi, giap nguoi, giau nguoi
tac nguoi » toc nguoi, tay nguoi, thuc nguoi
sach hoc » cach hoc, sach hoi, sach duoc
mach hoc » cach hoc, dich hoc, anh hoc
thu giao » thue giao, tu giao, chu giao
cac thu » cach thuc, cac thoi
so cac » sao cac, so cap, o cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( thuoc ((sach hoc) or (mach hoc)) tac nguoi ) or ( so cac thu giao nguoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thuoc ((sach hoc) OR (mach hoc)) tac nguoi ) OR ( so cac thu giao nguoi )).
• Adding a wildcard symbol may retrieve word variants: (( thuoc ((sach hoc) or (mach hoc)) tac nguoi ) or ( so cac thu giao nguoi ))*.