Perhaps you should try some spelling variations:
quang thanh » quan thanh, hoang thanh, muong thanh
thiet hach » thien hach, thuyet hach, thiet hai
thong cong » trong cong, tong cong, thong thong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
dung cong » dung trong
thanh ban » thanh san, thanh van, thanh bac
tranh va » tranh van, trang va, trinh va

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thiet hach - canh tranh va ((thong cong) or (dung cong)) quang thanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet hach - canh tranh va ((thong cong) OR (dung cong)) quang thanh ban.
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - canh tranh va ((thong cong) or (dung cong)) quang thanh ban*.