Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, thien van, hieu ve
vat hanh » vat thanh, van hanh, va hanh
ban hanh » ban hang
so sach » so sanh, bo sach, co sach
sach ly » sach y, sach lo, sach ty
ly vang » ly hang, ly van, ly quang
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
vang x » nang x

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly vang x ho. ((hieu van) OR (lieu va)) cam thuc ((vat hanh) or (ban hanh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly vang x ho. ((hieu van) OR (lieu va)) cam thuc ((vat hanh) OR (ban hanh)) doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ly vang x ho. ((hieu van) OR (lieu va)) cam thuc ((vat hanh) or (ban hanh)) doi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ly vang x ho. ((hieu van) OR (lieu va)) cam thuc ((vat hanh) or (ban hanh)) doi cua tre*.