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

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 ((hoi nang) or (hoi lang)) mai hoi. ((hieu van) or (hieu va)) am thuc dang hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((hoi nang) OR (hoi lang)) 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) or (hoi lang)) mai hoi. ((hieu van) or (hieu va)) am thuc dang hanh di cua vat*.