Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
vai cua » dai cua, hai cua, lai cua
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
sach tu » sach thu, cach tu, sach ty
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
tu nang » tru nang, tu nong, tu nano
ve cam » ve cham, ve cac, va cam
vi cua » di cua
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 tu nang ((x hoi) or (o hoi)). hieu ve cam duc van hanh ((vi cua) or (vai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu nang ((x hoi) OR (o hoi)). hieu ve cam duc van hanh ((vi cua) OR (vai cua)) triet.
• Adding a wildcard symbol may retrieve word variants: su sach tu nang ((x hoi) or (o hoi)). hieu ve cam duc van hanh ((vi cua) or (vai cua)) triet*.