Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
tang van » hoang van, trong van, tang luan
dang van » hoang van, hang va
qua cham » qua hai, qua cac, va cham
cham tuc » nham thuc, pham thuc, tham thuc
thanh vi » hanh vi, thanh ve, nhanh vi
thanh va » thanh van, hanh va, thanh ha
tuc van » thuc van, truc van, tuc va
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach _ ((tang van) or (dang van)) hoa. hieu qua cham tuc van ((thanh vi) or (thanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach _ ((tang van) OR (dang van)) hoa. hieu qua cham tuc van ((thanh vi) OR (thanh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: hoc sach _ ((tang van) or (dang van)) hoa. hieu qua cham tuc van ((thanh vi) or (thanh va)) cua tre*.