Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach tu » sach thu, cach tu, sach ty
tu xang » ty xang, tu lang, tu quang
cho hoc » khoa hoc
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
xuc van » duc van, luc van, vuc van
cua cau » cua cac, cua cay, cua can
cua chu » sua chua
ve cac » va cac, vien cac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu xang ((cho hoc) OR (co hoc)). hieu ve cac xuc van hanh vi ((cua cau) OR (cua chu))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu xang ((cho hoc) OR (co hoc)). hieu ve cac xuc van hanh vi ((cua cau) or (cua chu))~".
• Adding a wildcard symbol may retrieve word variants: toc sach tu xang ((cho hoc) OR (co hoc)). hieu ve cac xuc van hanh vi ((cua cau) or (cua chu))*.