Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua vat
lo nang » ho nang, ly nang, loai nang
nang ma » tang ma, sang ma, nang cao
te sach » toc sach
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh de » hanh ve, hanh kem
tu sach » thu sach, su sach, tu cach
ma hoi » mai hoi, xa hoi, ma hoa
de cua » le cua, te cua, dieu 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) OR (te sach)) lo nang ma hoi. ((hieu quan) OR (hieu qua)) nam thuc va hanh de cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) lo nang ma hoi. ((hieu quan) or (hieu qua)) nam thuc va hanh de cua viet~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) lo nang ma hoi. ((hieu quan) or (hieu qua)) nam thuc va hanh de cua viet*.