Perhaps you should try some spelling variations:
qua cham » qua cac, va cham, qua cua
vanh dai » van dai, vanh tai, lanh dao
va vanh » va van, va danh, va hanh
qua hai » qua hoat
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
loc va » hoc va, luc va
cua te » cua tu
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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 ky nang ((o hoi) or (o hai)). hieu ((qua cham) OR (qua hai)) loc va vanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoi) OR (o hai)). hieu ((qua cham) OR (qua hai)) loc va vanh dai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hoi) or (o hai)). hieu ((qua cham) OR (qua hai)) loc va vanh dai cua te*".