Perhaps you should try some spelling variations:
thiet tach » chiet tach, thuat tach
thien hach » thien thanh, hien hanh
nhung cong » dung cong, thong cong, nhung don
hanh hang » thanh hang, hang hang, hanh han
hang cong » dang cong, hang nong, bang cong
thanh van » thanh san, thanh toan, thanh phan

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 tach) or (thien hach)) - hanh hang va ((nhung cong) OR (hang cong)) thanh van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (thien hach)) - hanh hang va ((nhung cong) OR (hang cong)) thanh van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) or (thien hach)) - hanh hang va ((nhung cong) OR (hang cong)) thanh van ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) or (thien hach)) - hanh hang va ((nhung cong) OR (hang cong)) thanh van ban*.