Perhaps you should try some spelling variations:
khanh thi » nhanh thi, khanh thu, nhanh thai
van khanh » van thanh, van hanh, van anh
sach ky » sac ky, sach ty, sach kem
thi cuc » tai cuc
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
cuc tre » duc tre, cua tre, cuu tre
co hai » co dai, co hoi, o hai
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hai

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 (sach y)) nang ((o hoi) or (co hai)). hieu ve cac duc van khanh thi cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang ((o hoi) OR (co hai)). hieu ve cac duc van khanh thi cuc tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang ((o hoi) or (co hai)). hieu ve cac duc van khanh thi cuc tre*.