Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach, vu sach
dau xuc » dau xac, dau xua, dau nuoc
hieu va » lieu va, hieu qua
vu nang » vuc nang, va nang, vu dang
cua tre » cua te, cuu tre, cua triet
va dau » va dao
v nang » va nang, van nang, voi nang
vi cua » vai cua, di cua

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 ((v nang) or (vu nang)) xa hoi. hieu va dau xuc ((van hanh) OR (ban hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (vu nang)) xa hoi. hieu va dau xuc ((van hanh) OR (ban hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (vu nang)) xa hoi. hieu va dau xuc ((van hanh) OR (ban hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (vu nang)) xa hoi. hieu va dau xuc ((van hanh) OR (ban hanh)) vi cua tre*.