Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
thuc day » thuc dan
cuu tre » cua tre, cau tren, cau treo
mai hoi » mai khoi, lai hoi, mai doi
dai hoi » dai hoc, dai hai, dai moi
hieu ve » hieu va, hieu van
vi cuu » vi luu, vinh cuu
tu cao » cu cao, tu cac, vu cao
ve cam » ve cham, ve cac, va cam

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu cao ky nang ((mai hoi) OR (dai hoi)). hieu ve cam ((thuc day) OR (thuc vat)) thanh vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cao ky nang ((mai hoi) or (dai hoi)). hieu ve cam ((thuc day) OR (thuc vat)) thanh vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: tu cao ky nang ((mai hoi) or (dai hoi)). hieu ve cam ((thuc day) OR (thuc vat)) thanh vi cuu tre*.