Perhaps you should try some spelling variations:
cam thue » cam thu, nam thue, cam thiet
lam thue » nam thue, luat thue, lam thuoc
nang tai » hang tai, tang tai, sang tai
tai cua » thai cua, tai cuc, tri cua
va nang » van nang, da nang, cam nang
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
5 hoi » o 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 ((5 hoi) or (xa hoi)). hieu va ((cam thue) OR (lam thue)) va nang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((5 hoi) OR (xa hoi)). hieu va ((cam thue) OR (lam thue)) va nang tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((5 hoi) or (xa hoi)). hieu va ((cam thue) OR (lam thue)) va nang tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((5 hoi) or (xa hoi)). hieu va ((cam thue) OR (lam thue)) va nang tai cua tre*.