Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac quoc » cac nuoc, cac cuoc, cao quoc
quoc ban » quoc bao, quoc lan, quoc quan
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
ban anh » ban hanh, ban banh, ban danh
vai cua » dai cua, hai cua, lai cua
x hoi » xa hoi, x ho, 5 hoi
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 sach ky nang ((x hoi) OR (o hoi)). hieu van cac quoc ban anh ((vai cua) or (lai chau)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (o hoi)). hieu van cac quoc ban anh ((vai cua) OR (lai chau)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) OR (o hoi)). hieu van cac quoc ban anh ((vai cua) or (lai chau)) tre*".