Perhaps you should try some spelling variations:
thien van » thi van
sach dao » lanh dao
dao nang » cao nang, da nang, dai nang
hieu van » hieu va, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
ma hoi » xa hoi, ma hoa, me hoi
thu va » thuc va, thue va, tu va
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 dao nang ((ma hoi) OR (mai hoi)). ((hieu van) OR (thien van)) nam thu va hanh di cua vat~.
• Adding a wildcard symbol may retrieve word variants: tu sach dao nang ((ma hoi) or (mai hoi)). ((hieu van) or (thien van)) nam thu va hanh di cua vat*.