Perhaps you should try some spelling variations:
thanh dieu » thanh lieu, than dieu, hanh dieu
dieu cua » dieu tra
tu sach » thu sach, su sach, te sach
tang ma » tang van
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
luc va » tuc va, loc 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 y ((mang may) or (tang ma)) hoa. hieu ve cac ((luc va) OR (duc va)) thanh dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((mang may) OR (tang ma)) hoa. hieu ve cac ((luc va) OR (duc va)) thanh dieu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((mang may) or (tang ma)) hoa. hieu ve cac ((luc va) OR (duc va)) thanh dieu cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((mang may) or (tang ma)) hoa. hieu ve cac ((luc va) OR (duc va)) thanh dieu cua tre*.