Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh de » hanh ve, hanh kem
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
sach 2a » sach xa, sach ha, sach va
sach 2 » sach y
ma hoi » xa hoi, ma hoa, me hoi
ve cac » va cac, vien cac
de cua » le cua, te cua, dieu cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach 2) or (sach 2a)) tang ((ma hoi) or (mai hoi)). hieu ve cac duc van hanh de cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach 2) OR (sach 2a)) tang ((ma hoi) OR (mai hoi)). hieu ve cac duc van hanh de cua tu.
• Adding a wildcard symbol may retrieve word variants: te ((sach 2) or (sach 2a)) tang ((ma hoi) or (mai hoi)). hieu ve cac duc van hanh de cua tu*.