Perhaps you should try some spelling variations:
khan than » phan than, khoan thanh, khanh thanh
cau tren » cu tren, dau tren, ca tren
than cau » toan cau, phan cau, than cap
van khan » van khanh, van khang, van phan
xuc van » duc van, luc van, vuc van
cac xuc » cam xuc, cac nuoc, chat xuc
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
ve cac » va cac, vien cac
sac ky » cac ky, sai ky
o hoc » co hoc, mo hoc, so hoc
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: tu ((sach ky) or (sac ky)) nang ((o hoc) or (o hai)). hieu ve cac xuc van khan than cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang ((o hoc) OR (o hai)). hieu ve cac xuc van khan than cau tren.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang ((o hoc) or (o hai)). hieu ve cac xuc van khan than cau tren*.