Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh hai » thanh hai, nhanh hai, hang hai
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cac truc » cau truc, cac tru, cac trung
qua cac » cua cac
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
hai su » hai vu, lai su, hai so
o hoa » do hoa, so hoa, o ha
o hoi » co hoi, o hoc
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang ((((o hoi) OR (o hoa))) or (o hai)). hieu qua cac truc van hanh hai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((((o hoi) OR (o hoa))) OR (o hai)). hieu qua cac truc van hanh hai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((((o hoi) OR (o hoa))) or (o hai)). hieu qua cac truc van hanh hai su triet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((((o hoi) OR (o hoa))) or (o hai)). hieu qua cac truc van hanh hai su triet*.