Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van ban
su sach » so sach
van anh » van thanh, tuan anh, van minh
dau xac » dau xay, dan xac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
vu sach » vu bach, vu khach
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
va dau » va dao
x hoi » xa hoi, o hoi, x ho

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