Perhaps you should try some spelling variations:
hieu vanh » hieu manh, chieu xanh, hieu nganh
thanh hoa » thanh pho
lang nong » hang nong, lang dong, lang song
hieu van » hieu va, thien van, lieu va
hoa lang » hoa dan, hoa van
thon dan » thong dan, tho dan, thong danh
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

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 van) or (hieu vanh)) - thanh hoa lang nong thon dan than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu van) OR (hieu vanh)) - thanh hoa lang nong thon dan than tap*.