Perhaps you should try some spelling variations:
cuc triet » cua triet, su triet, cac trieu
hanh tai » thanh tai, hang tai, han tai
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
va cham » va chat, va tham
y nang » ky nang, ly nang, v nang
ro hoi » co hoi, mo hoi, ro doi
xuc va » tuc va, luc va, xac va
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((ro hoi) OR (o hoi)). hieu va cham ((xuc va) OR (duc va)) hanh tai cuc triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((ro hoi) OR (o hoi)). hieu va cham ((xuc va) or (duc va)) hanh tai cuc triet~".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((ro hoi) OR (o hoi)). hieu va cham ((xuc va) or (duc va)) hanh tai cuc triet*.