Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh dai » thanh hai, thanh tai, thanh dat
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
van cac » van hac, van cau, van bac
cac dai » cac dan, cac bai, can dai
dai ban » dai han, tai ban, di ban
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: su sach ly nang ((x hoi) or (o hoi)). hieu van cac dai ban thanh dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((x hoi) OR (o hoi)). hieu van cac dai ban thanh dai cua triet.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((x hoi) or (o hoi)). hieu van cac dai ban thanh dai cua triet*.