Perhaps you should try some spelling variations:
hanh hanh » hanh han, xanh hanh, nhanh thanh
cac thuc » cach thuc, cac thu, can thuc
hanh doi » thanh doi, hanh noi, hang doi
su sach » so sach, vu sach
tang ma » tang van
hieu ve » hieu va, hieu van
cua tre » cuu tre, cua triet, dua tren
ve cac » va cac, vien cac
cua te » cua tu

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 y ((mang may) or (tang ma)) hoi. hieu ve cac thuc hanh hanh doi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((mang may) OR (tang ma)) hoi. hieu ve cac thuc hanh hanh doi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((mang may) or (tang ma)) hoi. hieu ve cac thuc hanh hanh doi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: su sach y ((mang may) or (tang ma)) hoi. hieu ve cac thuc hanh hanh doi ((cua tre) OR (cua te))*.