Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
dau tren » dau tien, dau tieng, dau trong
dat tren » dat trong, dua tren
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang doc, nang noi
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
co hoi » co hoc, co loi
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: thuoc sach ky nang co hoi. hieu ve cac duc va hanh ve ((dau tren) OR (dat tren))~.
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky nang co hoi. hieu ve cac duc va hanh ve ((dau tren) or (dat tren))*.