Perhaps you should try some spelling variations:
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
ma hoi » xa hoi, ma hoa, me hoi
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, duc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky tang ((ma hoi) or (mai hoi)). hieu ve cam ((tuc va) or (tuc xa)) hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ((ma hoi) OR (mai hoi)). hieu ve cam ((tuc va) OR (tuc xa)) hanh vi cua vat.
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ((ma hoi) or (mai hoi)). hieu ve cam ((tuc va) or (tuc xa)) hanh vi cua vat*.