Perhaps you should try some spelling variations:
kho tang » cao tang
sach kho » bach khoa, sach dao, sach nha
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ca viet » va viet, co viet, hoa viet
ve cac » va cac, vien cac
ma hoi » xa hoi, ma hoa, me hoi
tuc va » thuc va, truc va, duc va
vi ca » vit ca, li ca, va ca

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 kho tang ((ma hoi) or (mai hoi)). hieu ve cac ((tuc va) or (tuc xa)) hanh vi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach kho tang ((ma hoi) OR (mai hoi)). hieu ve cac ((tuc va) OR (tuc xa)) hanh vi ca viet.
• Adding a wildcard symbol may retrieve word variants: su sach kho tang ((ma hoi) or (mai hoi)). hieu ve cac ((tuc va) or (tuc xa)) hanh vi ca viet*.