Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
thuc ban » thuoc ban, thuc dan, thu ban
thanh de » hanh de, thanh ve, thanh do
thanh di » thanh doi, thanh do, thanh dinh
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
su viet » so viet
va cam » va cham, va cac, va cao

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 ty ((nang x) or (lang xa)) hoi. lieu va cam thuc ban ((thanh di) OR (thanh de)) su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang x) OR (lang xa)) hoi. lieu va cam thuc ban ((thanh di) OR (thanh de)) su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang x) or (lang xa)) hoi. lieu va cam thuc ban ((thanh di) OR (thanh de)) su viet".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang x) or (lang xa)) hoi. lieu va cam thuc ban ((thanh di) OR (thanh de)) su viet*.