Perhaps you should try some spelling variations:
cong thuc » cong tac
thuc cong » thuoc cong, thu cong, chuc cong
cong cong » cong dong, trong cong, dung cong
cong lang » cong vang, cong luong, cong quang
lang phan » nang phan, lang thang, lang phong
doc hieu » hoc thieu, hoc hien
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) OR (toc thieu)) sach - thanh cong thuc cong cong lang phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) OR (toc thieu)) sach - thanh cong thuc cong cong lang phan dau".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) OR (toc thieu)) sach - thanh cong thuc cong cong lang phan dau*.