Perhaps you should try some spelling variations:
dang mam » dang nam, dang mau, dang mat
cam thuc » am thuc, nam thuc, cam thu
dang ma » dang mau, dang mat, tang ma
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
te cac » tu cac, ve cac, te cao
ve cam » ve cham, ve cac, va cam
va cua » va chua, via cua, ca cua

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

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