Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
quan nam » quang nam, xuan nam, quan am
nam thuc » nam thuoc, am thuc, nam thu
thuc va » thuc vat, thuc dan, thuc day
nang co » nang cao, nang doc, nang noi
lang ra » lang ha, lang xa, lang va
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cua tu » cua tuc, cua cu, cua te
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
cua su » qua su

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 ((nang co) or (lang ra)) hoi. hieu quan nam thuc va danh vi ((cua tu) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang co) OR (lang ra)) hoi. hieu quan nam thuc va danh vi ((cua tu) OR (cua su)).
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang co) or (lang ra)) hoi. hieu quan nam thuc va danh vi ((cua tu) or (cua su))*.