Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hieu van » thien van, lieu va, hieu ve
thuoc va » thuc va, thuoc ma, thuong va
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
sach lo » sach dao, sach doi, sach hoi
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
lo nang » ho nang, ly nang, loai nang
ca viet » va viet, co viet, hoa viet
ma hoi » xa hoi, ma hoa, me hoi
di ca » di cau, di cua, doi ca

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