Perhaps you should try some spelling variations:
sanh van » san van, anh van, canh van
van hanh » van thanh, ban hanh, van anh
cau thuc » cuu thuc, can thuc, cau phuc
so sanh » do sanh
hanh de » hanh ve, hanh kem
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
de cua » le cua, te cua, dieu cua
x hoi » xa hoi, o hoi, x ho
ban x » ban xu, ban _, ban 1

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

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