Perhaps you should try some spelling variations:
dang hanh » dang thanh, ban hanh, dang van
thuc dang » thuoc dang, thuc dan, thuc dung
sach hoi » sach doi, sach moi, cach thoi
hoi nang » hoi lang, ho nang, hoa nang
hieu van » thien van, lieu va, hieu ve
hanh di » hanh vi, hanh de, hang di
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi
di cua » dai cua, doi cua, de cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoi nang ((ma hoi) OR (mai hoi)). ((hieu van) OR (hieu va)) am thuc dang hanh di cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoi nang ((ma hoi) OR (mai hoi)). ((hieu van) or (hieu va)) am thuc dang hanh di cua vat~".
• Adding a wildcard symbol may retrieve word variants: tu sach hoi nang ((ma hoi) OR (mai hoi)). ((hieu van) or (hieu va)) am thuc dang hanh di cua vat*.