Perhaps you should try some spelling variations:
doanh doanh » toan doanh, doanh hoan, doanh thanh
thiet hach » thien hach, thuyet hach, thiet hai
hoc thiet » hoc thieu, hoc thuyet, hoc hien
cua tong » cua dong, cua nong, cua song
dan toan » van toan, dan than, manh toan
van than » van thanh, van thang, van tuan

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 - doanh doanh ((cua tong) OR (cua cong)) huong ((dan toan) or (van than)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet hach - doanh doanh ((cua tong) OR (cua cong)) huong ((dan toan) OR (van than)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet hach - doanh doanh ((cua tong) OR (cua cong)) huong ((dan toan) or (van than)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - doanh doanh ((cua tong) OR (cua cong)) huong ((dan toan) or (van than)) cau*.