Perhaps you should try some spelling variations:
dung sai » dung tai, dung va, dung dat
vat dung » van dung, va dung, viet dung
tu sach » thu sach, su sach, tu cach
sai cua » dai cua, hai cua, lai cua
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
hieu va » lieu va, hieu qua
te sach » toc sach
nang o » nang co, nang ho, nang ro
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: ((tu sach) or (te sach)) ky nang o hoi. hieu va ((cac duc) or (cac dac)) vat dung sai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang o hoi. hieu va ((cac duc) OR (cac dac)) vat dung sai cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang o hoi. hieu va ((cac duc) or (cac dac)) vat dung sai cua te*.