Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
dua tren » dung tren
sach ky » sac ky, sach y, sach ty
van hai » van ha, van chat, van hanh
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
van cac » van hac, van cau, van bac
co hoi » co hoc
tac va » tac da, tac xa, tuc va
ve dua » ve du, ve mua, de dua

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: thuat sach ky nang ((co hoi) OR (co loi)). hieu ((van cac) OR (van hai)) tac va hanh ve dua tren~.
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((co hoi) or (co loi)). hieu ((van cac) or (van hai)) tac va hanh ve dua tren*.