Perhaps you should try some spelling variations:
hang vai » hang va, hang tai, hang hai
ban hang » ngan hang
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, lai cua
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
tu sach » thu sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
co hoi » co hoc, co loi
ve cac » va cac, vien cac
y nang » ky nang, ly nang, v nang
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: ((tu sach) OR (su sach)) y nang ((x hoi) or (co hoi)). hieu ve cac duc ban hang vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang ((x hoi) OR (co hoi)). hieu ve cac duc ban hang vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang ((x hoi) or (co hoi)). hieu ve cac duc ban hang vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang ((x hoi) or (co hoi)). hieu ve cac duc ban hang vai cua tre*.