Perhaps you should try some spelling variations:
khanh thanh » nhanh thanh, thanh thanh, phan thanh
khanh thai » nhanh thai, khanh thuan, thanh hai
cau treo » cau theo, cau tren, cau triet
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, 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 ky nang ((o hoi) or (o hai)). hieu ve cac luc van ((khanh thai) or (khanh thanh)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoi) OR (o hai)). hieu ve cac luc van ((khanh thai) OR (khanh thanh)) cau treo.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoi) or (o hai)). hieu ve cac luc van ((khanh thai) or (khanh thanh)) cau treo*.