Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hanh ve » hanh vi, hanh va, hanh kem
va hanh » van hanh, va thanh, va danh
cac bac » cac bai, cac ban, cac cach
sach ky » sac ky, sach y, sach ty
cac tac » cac toc, cac dac, cac tai
hieu ve » hieu va, hieu van
cu tren » tu tren, dua tren
co hoi » co hoc
ve cu » ve cau, ve chu, ve cua

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 ve ((cac tac) OR (cac bac)) va hanh ve cu tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ((co hoi) or (co loi)). hieu ve ((cac tac) OR (cac bac)) va hanh ve cu tren~".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((co hoi) or (co loi)). hieu ve ((cac tac) OR (cac bac)) va hanh ve cu tren*.