Perhaps you should try some spelling variations:
khanh thai » nhanh thai, khanh thanh, khanh thuan
van khanh » van thanh, van hanh, van anh
hieu vien » hieu hien, hieu viec, thieu nien
cau tren » cu tren, dau tren, ca tren
vien cac » vien bach, vien dai, vien da
sach ty » sach y, sach tu, sach thu
cac xuc » cam xuc, cac nuoc, chat xuc
xuc van » duc van, luc van, vuc van
ty hang » ly hang, ty xang, thi hang
cuu tre » cua tre, cau treo
tu sach » thu sach, su sach, te sach
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 ty hang ((o hoi) or (o hai)). hieu vien cac xuc van khanh thai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang ((o hoi) OR (o hai)). hieu vien cac xuc van khanh thai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty hang ((o hoi) or (o hai)). hieu vien cac xuc van khanh thai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty hang ((o hoi) or (o hai)). hieu vien cac xuc van khanh thai ((cuu tre) OR (cau tren))*.