Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thuc van » thuc vat, thuc dan, thuc va
thanh de » hanh de, thanh ve, thanh do
thanh di » thanh doi, thanh do, thanh dinh
hieu he » hieu ve, hiem he, hieu le
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
he nam » ha nam, nghe nam
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach y) or (sac ky)) nang ma hoi. hieu he nam thuc van ((thanh di) OR (thanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach y) OR (sac ky)) nang ma hoi. hieu he nam thuc van ((thanh di) OR (thanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach y) or (sac ky)) nang ma hoi. hieu he nam thuc van ((thanh di) OR (thanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach y) or (sac ky)) nang ma hoi. hieu he nam thuc van ((thanh di) OR (thanh de)) cua tre*.