Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
thu hanh » thuc hanh, thu thanh, thuy hanh
hanh doi » hanh noi, hang doi, hanh moi
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
lang xa » lang ha, dang xay, lang van
am thu » am thuc, nam thu, cam thu
ve am » va am

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