Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
tranh cua » doanh cua
manh toan » thanh toan, anh tuan, tinh toan
manh cua » doanh cua, ban cua
dan toan » van toan, dan than, xuan toan

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 - canh ((tranh cua) or (manh cua)) nhung cong ((dan toan) OR (manh toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - canh ((tranh cua) OR (manh cua)) nhung cong ((dan toan) OR (manh toan)) ban*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - canh ((tranh cua) or (manh cua)) nhung cong ((dan toan) OR (manh toan)) ban*".