Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
vien cac » vien bach, vien dai, vien da
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
co hoi » co hoc
ve cac » va cac
xuc va » duc va, tuc va, luc va
ve cau » ke cau, va cau, le cau

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