Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang van » dang van, hoang van, giang van
tang van » dang van, hoang van, trong van
thanh vi » hanh vi, thanh va, nhanh vi
thanh ve » hanh ve, thanh va, thanh vien
qua hai » qua hoat
hai tuc » thai tuc, hai cuc, thai thuc
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: toc sach _ ((lang van) OR (tang van)) hoa. hieu qua hai tuc van ((thanh vi) or (thanh ve)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach _ ((lang van) OR (tang van)) hoa. hieu qua hai tuc van ((thanh vi) OR (thanh ve)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach _ ((lang van) OR (tang van)) hoa. hieu qua hai tuc van ((thanh vi) or (thanh ve)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach _ ((lang van) OR (tang van)) hoa. hieu qua hai tuc van ((thanh vi) or (thanh ve)) cua tre*.