Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, truc nano
ban hanh » ban hang
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
nam cuc » nam cac, nam cua, nam thuc
cuc ban » cua ban, cac ban, cuu ban
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay
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 va nam cuc 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 va nam cuc ban hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) tru nang x hoi. hieu va nam cuc ban hanh vi cua tre*.