Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hai truc » dai truc, hai trac, hang truc
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach, vu sach
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
van hai » van ha, van chat, van phan
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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: su sach ((ky lang) OR (ky dang)) xa hoi. hieu van hai truc ((ban hanh) OR (van hanh)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) OR (ky dang)) xa hoi. hieu van hai truc ((ban hanh) or (van hanh)) vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) OR (ky dang)) xa hoi. hieu van hai truc ((ban hanh) or (van hanh)) vi cua tre*.