Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, truc nano
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
van cam » van nam, van lam, van cau
cuc ban » cac ban, cuu ban, duc ban
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
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)) tru nang x hoi. hieu van cam ((cuc ban) OR (cua ban)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) tru nang x hoi. hieu van cam ((cuc ban) OR (cua ban)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) tru nang x hoi. hieu van cam ((cuc ban) OR (cua ban)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) tru nang x hoi. hieu van cam ((cuc ban) OR (cua ban)) hanh vi cua tre*.