Perhaps you should try some spelling variations:
qua cham » qua hai, qua cac, va cham
vanh dai » van dai, vanh tai, lanh dao
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang o » nang co, nang ho, nang ro
luc va » duc va, tuc va
loc va » hoc va
cua te » cua tu
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: vu sach ky nang o hoi. hieu qua cham ((luc va) or (loc va)) vanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang o hoi. hieu qua cham ((luc va) OR (loc va)) vanh dai cua te*.