Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
su triet » su viet, su tien, ve triet
doc sach » hoc sach, toc sach, nuoc sach
quoc ban » quoc bao, quoc lan, quoc quan
hieu van » hieu va, thien van, lieu va
nuoc ban » nuoc san, buoc ban, duoc ban
te sach » toc sach
van cac » van hac, van cau, van bac
doi su » oi su, don su, voi su
x hoi » xa hoi, o hoi, x ho

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 (doc sach)) ky nang x hoi. hieu van cac ((nuoc ban) OR (quoc ban)) thanh doi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (doc sach)) ky nang x hoi. hieu van cac ((nuoc ban) OR (quoc ban)) thanh doi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (doc sach)) ky nang x hoi. hieu van cac ((nuoc ban) OR (quoc ban)) thanh doi su triet".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (doc sach)) ky nang x hoi. hieu van cac ((nuoc ban) OR (quoc ban)) thanh doi su triet*.