Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cac truc » cau truc, cac tru, cac trung
dat tren » dat trong, dua tren
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
ca tren » cau tren, cu tren, la tren
co hoi » co loi

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