Perhaps you should try some spelling variations:
thanh lam » thanh lap, hanh lam, thanh nam
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
van cau » van dau, van hau, van chat
cau duc » cao duc, cau luc, chu duc
nang o » nang co, nang ho, nang ro
tu san » thu san, tu ban, tu can
tu sac » tu sach, tu cac, tu bac
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sac) OR (tu san)) ky nang o hoi. hieu van cau duc va ((thanh lam) or (thanh san)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu san)) ky nang o hoi. hieu van cau duc va ((thanh lam) OR (thanh san)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sac) OR (tu san)) ky nang o hoi. hieu van cau duc va ((thanh lam) or (thanh san)) cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sac) OR (tu san)) ky nang o hoi. hieu van cau duc va ((thanh lam) or (thanh san)) cua viet*.