Perhaps you should try some spelling variations:
tai khoa » da khoa, noi khoa
hanh tai » thanh tai, hang tai, han tai
cua tre » cua te, cuu tre, cua triet
ky dang » ky nang, ky danh
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
van tai » von tai, van tuan
cac tuc » cac toc, cac tu, cac tac
tu sac » tu sach, tu cac, tu san
tuc va » thuc va, truc va, tuc xa
sac ky » cac ky, sai ky
ve cac » va cac, vien cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky dang ((mai hoi) or (tai khoa)). hieu ve cac tuc va ((hanh tai) or (van tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky dang ((mai hoi) OR (tai khoa)). hieu ve cac tuc va ((hanh tai) OR (van tai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky dang ((mai hoi) or (tai khoa)). hieu ve cac tuc va ((hanh tai) or (van tai)) cua tre*.