Perhaps you should try some spelling variations:
van khanh » van thanh, van hanh, van anh
khanh thi » nhanh thi, khanh thu, nhanh thai
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
thi cuc » tai cuc
cuc tre » duc tre, cua tre, cuu tre
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hoa
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 y nang ((o hoi) or (o hai)). hieu ve cac vuc van khanh thi cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoi) OR (o hai)). hieu ve cac vuc van khanh thi cuc tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoi) or (o hai)). hieu ve cac vuc van khanh thi cuc tre*.