Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
vanh dai » van dai, vanh tai, lanh dao
toc sach » hoc sach, doc sach, thuoc sach
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh
qua cac » cua cac
ha hoi » hoa hoi, ha noi, xa hoi
luc va » duc va, tuc va
loc va » hoc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ky dang ha hoi. hieu qua cac ((luc va) or (loc va)) vanh dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky dang ha hoi. hieu qua cac ((luc va) OR (loc va)) vanh dai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky dang ha hoi. hieu qua cac ((luc va) or (loc va)) vanh dai cua triet".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky dang ha hoi. hieu qua cac ((luc va) or (loc va)) vanh dai cua triet*.