Perhaps you should try some spelling variations:
khanh tai » thanh tai, hanh tai, nhanh thai
van khanh » van thanh, van hanh, van anh
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac xuc » cac nuoc, chat xuc, cac cuoc
cuc tre » duc tre, cua tre, cuu tre
y nang » ky nang, ly nang, v nang
co dai » co dan, do dai
o hoc » co hoc, mo hoc, so hoc

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 hoc) or (co dai)). hieu ve ((cac xuc) OR (cam xuc)) van khanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoc) OR (co dai)). hieu ve ((cac xuc) OR (cam xuc)) van khanh tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((o hoc) or (co dai)). hieu ve ((cac xuc) OR (cam xuc)) van khanh tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoc) or (co dai)). hieu ve ((cac xuc) OR (cam xuc)) van khanh tai cuc tre*.