Perhaps you should try some spelling variations:
thanh dong » thanh duong, thanh cong, hanh dong
hang nong » thang long
hoc hieu » hoc thieu, hoc hien, doc hieu
hieu luc » hieu luat, hieu qua
dong cua » dung cua, cong cua, huong cua
than tap » toan tap, han tap, than cap
phan tap » phan lap, han tap, pha tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu luc - thanh dong cua ((hang nong) or (han tong)) dan ((than tap) or (phan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu luc - thanh dong cua ((hang nong) OR (han tong)) dan ((than tap) OR (phan tap)).
• Adding a wildcard symbol may retrieve word variants: hoc hieu luc - thanh dong cua ((hang nong) or (han tong)) dan ((than tap) or (phan tap))*.