Perhaps you should try some spelling variations:
cam thue » cam thu, lam thue, nam thue
thai cua » than cua, tai cuc, tri cua
tu sach » thu sach, su sach, te sach
tai cua » tai cuc, tri cua, dai cua
va nang » van nang, da nang, cam nang
thue va » thuc va, thuyet va, thuc vat
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
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: tu sach y nang ((x hoi) or (o hoi)). hieu va cam thue va nang ((tai cua) OR (thai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (o hoi)). hieu va cam thue va nang ((tai cua) OR (thai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) or (o hoi)). hieu va cam thue va nang ((tai cua) OR (thai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (o hoi)). hieu va cam thue va nang ((tai cua) OR (thai cua)) tre*.