Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
cau tren » cu tren, dau tren, cau treo
anh thai » anh thi, anh tai, nhanh thai
cac xuc » cam xuc, cac nuoc, chat xuc
van anh » van thanh, tuan anh, van minh
xuc van » duc van, luc van, vuc van
tu sach » thu sach, su sach, te sach
ca tren » cu tren, la tren, co tren
sach ky » sac ky, sach y, sach ty
o hai » co hai, so hai, o lai
o hoa » do hoa, so hoa, o ha

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 hoa) or (o hai)). hieu vien cac xuc van anh thai ((cau tren) or (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoa) OR (o hai)). hieu vien cac xuc van anh thai ((cau tren) OR (ca tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoa) or (o hai)). hieu vien cac xuc van anh thai ((cau tren) or (ca tren))*.