Perhaps you should try some spelling variations:
hieu cua » hieu qua, dieu cua, bieu cua
tinh tai » trinh tai, tinh thai, tinh hai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
tang ma » tang van
lang xa » lang ha, dang xay, lang van
va tinh » may tinh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
du va » dau va, tu va, su va

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 ty ((((tang ma) OR (mang may))) or (lang xa)) hoi. hieu cua cac du va tinh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((((tang ma) OR (mang may))) OR (lang xa)) hoi. hieu cua cac du va tinh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((((tang ma) OR (mang may))) or (lang xa)) hoi. hieu cua cac du va tinh tai cua tre*".