Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tang hanh » tang thanh, dang hanh, nang hanh
hieu van » hieu va, thien van, lieu va
tan hanh » tan thanh, toan hanh, tran hanh
tham duc » pham duc, tham du, than duc
van tham » van thanh, van tuan, van chat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
lai cua » dai cua, hai cua, lai chau
su sach » so sach, vu sach
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 ty nang ((x hoi) or (o hoi)). hieu van tham duc ((tan hanh) OR (tang hanh)) lai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((x hoi) OR (o hoi)). hieu van tham duc ((tan hanh) OR (tang hanh)) lai cua triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((x hoi) or (o hoi)). hieu van tham duc ((tan hanh) OR (tang hanh)) lai cua triet*".