Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
may khoa » da khoa, ly khoa, y khoa
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
qua ban » qua quan
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
may hoa » ma hoa, day hoa, mai hoa
ky mang » ky nang, ke mang, ky dang
va lam » van lam, va lap

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 ky mang ((may hoa) OR (may khoa)). hieu va lam ((cua ban) or (qua ban)) thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky mang ((may hoa) OR (may khoa)). hieu va lam ((cua ban) OR (qua ban)) thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky mang ((may hoa) OR (may khoa)). hieu va lam ((cua ban) or (qua ban)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky mang ((may hoa) OR (may khoa)). hieu va lam ((cua ban) or (qua ban)) thanh vai cua tre*.