Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
van cac » van hac, van cau, van bac
mai hoi » mai khoi, dai hoi, lai hoi
ty hang » ly hang, ty xang, thi hang
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua su

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) or (toc sach)) ty hang ((ma hoa) or (mai hoi)). hieu van cac duc van hanh vi cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty hang ((ma hoa) OR (mai hoi)). hieu van cac duc van hanh vi cua cu.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty hang ((ma hoa) or (mai hoi)). hieu van cac duc van hanh vi cua cu*.