Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
duoc hoi » quoc hoi, duoc hoc, duoc si
hanh ve » hanh va, hanh kem
dai luc » dai luoc, dai luan, dai thuc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
doc hoi » hoc hoi, doc hai, doi hoi
ca tren » cau tren, cu tren, la tren
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((doc hoi) OR (duoc hoi)). hieu hien dai luc va ((hanh ve) or (hanh vi)) ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((doc hoi) OR (duoc hoi)). hieu hien dai luc va ((hanh ve) OR (hanh vi)) ca tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((doc hoi) OR (duoc hoi)). hieu hien dai luc va ((hanh ve) or (hanh vi)) ca tren*".