Perhaps you should try some spelling variations:
thanh dien » thanh vien, thanh nien, thanh hien
toc sach » hoc sach, doc sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
dien cua » dieu cua, dien cuc, dien cu
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky nang ((o hoi) OR (o hai)). hieu ve cac duc va thanh dien cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ((o hoi) OR (o hai)). hieu ve cac duc va thanh dien cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ((o hoi) OR (o hai)). hieu ve cac duc va thanh dien cua tre*.