Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
cac dat » cac dan, cai dat, cac dai
sach ty » sach y, sach tu, sach thu
van cac » van hac, van cau, van bac
sach ky » sac ky, sach y, sach kem
mai hoi » mai khoi, dai hoi, lai hoi
vi cua » vai cua, di cua
ma hoi » xa hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) OR (sach ty)) nang ((ma hoi) or (mai hoi)). hieu van cac dat va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) nang ((ma hoi) OR (mai hoi)). hieu van cac dat va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach ty)) nang ((ma hoi) or (mai hoi)). hieu van cac dat va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach ty)) nang ((ma hoi) or (mai hoi)). hieu van cac dat va hanh vi cua vat*.