Perhaps you should try some spelling variations:
thanh duc » thach duc, than duc, thinh duc
thanh lap » thanh san, phan lap, thanh hai
hanh lai » hanh lam, hanh tai, thanh loi
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang cao hoi. ((hieu va) OR (hieu qua)) thanh duc va ((hanh lai) or (thanh lap)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang cao hoi. ((hieu va) OR (hieu qua)) thanh duc va ((hanh lai) OR (thanh lap)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang cao hoi. ((hieu va) OR (hieu qua)) thanh duc va ((hanh lai) or (thanh lap)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang cao hoi. ((hieu va) OR (hieu qua)) thanh duc va ((hanh lai) or (thanh lap)) cua tre*.