Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, duc man
tai cua » thai cua, tai cuc, tri cua
dua ban » dia ban, cua ban, qua ban
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
cao hoc » co hoc, cho hoc, chat hoc
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: tu sach ky nang cao hoc. ((hieu va) OR (lieu va)) cam ((duc ban) or (dua ban)) thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoc. ((hieu va) OR (lieu va)) cam ((duc ban) OR (dua ban)) thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cao hoc. ((hieu va) OR (lieu va)) cam ((duc ban) or (dua ban)) thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoc. ((hieu va) OR (lieu va)) cam ((duc ban) or (dua ban)) thanh tai cua tre*.