Perhaps you should try some spelling variations:
khanh thi » nhanh thi, khanh thu, nhanh thai
van khanh » van thanh, van hanh, van anh
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
vien cac » vien bach, vien dai, vien da
tu sach » thu sach, su sach, te sach
thi cuc » tai cuc
luc van » luoc van, luu van, duc van
cuc tre » duc tre, cua tre, cuu tre
ve cac » va cac
o hai » co hai, so hai, o lai
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 tru nang ((o hoc) or (o hai)). hieu ((ve cac) or (vien cac)) luc van khanh thi cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tru nang ((o hoc) OR (o hai)). hieu ((ve cac) OR (vien cac)) luc van khanh thi cuc tre.
• Adding a wildcard symbol may retrieve word variants: tu sach tru nang ((o hoc) or (o hai)). hieu ((ve cac) or (vien cac)) luc van khanh thi cuc tre*.