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