Perhaps you should try some spelling variations:
phan thanh » pham thanh, ban thanh, van thanh
thanh sinh » thanh binh, thanh tinh, thanh vinh
quan phan » quang phan, luan phan, qua phan
sinh cua » manh cua, dinh cuu, sinh va
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
va nam » van nam, ha nam
va nay » va ngay, va cay
o hoi » o hoc, o hai, o hoa

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 y nang ((o hoi) OR (co hoi)). lieu ((va nam) or (va nay)) quan phan thanh sinh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoi) OR (co hoi)). lieu ((va nam) OR (va nay)) quan phan thanh sinh cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((o hoi) OR (co hoi)). lieu ((va nam) or (va nay)) quan phan thanh sinh cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoi) OR (co hoi)). lieu ((va nam) or (va nay)) quan phan thanh sinh cua tre*.