Perhaps you should try some spelling variations:
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
thuc va » thuc vat, thuc dan, thuc day
mai hoi » mai khoi, dai hoi, lai hoi
tuc va » truc va, tuc xa, duc va
so sac » so sach, so dac
ve cam » ve cham, ve cac, va cam
sac ky » cac ky, sai ky
ma hoi » xa hoi, ma hoa, me hoi
vi hoa » voi hoa, vi hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sac ky dang ((ma hoi) OR (mai hoi)). hieu ve cam ((tuc va) or (thuc va)) hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sac ky dang ((ma hoi) OR (mai hoi)). hieu ve cam ((tuc va) OR (thuc va)) hanh vi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sac ky dang ((ma hoi) OR (mai hoi)). hieu ve cam ((tuc va) or (thuc va)) hanh vi hoa viet".
• Adding a wildcard symbol may retrieve word variants: so sac ky dang ((ma hoi) OR (mai hoi)). hieu ve cam ((tuc va) or (thuc va)) hanh vi hoa viet*.