Perhaps you should try some spelling variations:
trong thuong » thong thuong, trong tuong, cong thuong
khuyet danh » thuyet dan, thuyet anh
hoc khuyet » hoc thuyet, hoc chuyen, nom khuyet
thuong dan » huong dan, thuong han, thuong dam
dung tam » duong tam, dung tai, dung lam
dan van » dang van, doan van, dao van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc khuyet danh - manh ((dung tam) or (trung tam)) trong thuong dan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc khuyet danh - manh ((dung tam) OR (trung tam)) trong thuong dan van ban.
• Adding a wildcard symbol may retrieve word variants: hoc khuyet danh - manh ((dung tam) or (trung tam)) trong thuong dan van ban*.