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