Perhaps you should try some spelling variations:
dung sai » dung tai, dung va, dung dat
su sach » so sach
sai cua » dai cua, hai cua, lai cua
thu xac » thau xay
hieu he » hieu ve, hiem he, hieu le
cua tre » cua te, cuu tre, cua triet
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty xang, ty hang
vu sach » vu bach, vu khach
thu xa » thu ha, thu xe, thu ba
he nam » ha nam, nghe nam

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) OR (vu sach)) ty nang cao hoi. hieu he nam ((thu xa) or (thu xac)) dung sai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ty nang cao hoi. hieu he nam ((thu xa) OR (thu xac)) dung sai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) ty nang cao hoi. hieu he nam ((thu xa) or (thu xac)) dung sai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (vu sach)) ty nang cao hoi. hieu he nam ((thu xa) or (thu xac)) dung sai cua tre*.