Perhaps you should try some spelling variations:
tu cach » tu cac
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
van dai » vanh dai, van dao, van hai
luc va » duc va, tuc va, loc va
cua te » cua tu
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (tu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cac luc va van dai cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (tu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cac luc va van dai cua te~".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (tu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cac luc va van dai cua te*.