Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, mua ban
vai cua » dai cua, hai cua, lai cua
qua ban » cua ban, qua quan
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
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 ma hoa. ((hieu va) OR (lieu va)) lam ((dua ban) or (qua ban)) thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoa. ((hieu va) OR (lieu va)) lam ((dua ban) OR (qua ban)) thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoa. ((hieu va) OR (lieu va)) lam ((dua ban) or (qua ban)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoa. ((hieu va) OR (lieu va)) lam ((dua ban) or (qua ban)) thanh vai cua tre*.