Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
tan thanh » tran thanh, tang thanh, toan thanh
hieu van » hieu va, thien van, lieu va
van cua » vang cua, ban cua, dan cua
luc tan » luc tai, duc tan, luc tam
bao luc » bao thuc
van bao » van ban, van dao
tu sach » thu sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 (o hoi)). hieu van bao luc tan thanh van 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 (o hoi)). hieu van bao luc tan thanh van 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 (o hoi)). hieu van bao luc tan thanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) y nang ((x hoi) OR (o hoi)). hieu van bao luc tan thanh van cua tre*.