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 cua
cua nhung » va nhung
van toan » van tan, van thanh, manh toan
dan than » dan chan, ban than, van than
van tuan » van quan, van ban, anh 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 tach - canh tranh cua nhung cong ((((van toan) or (dan than))) or (van tuan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - canh tranh cua nhung cong ((((van toan) OR (dan than))) OR (van tuan)) cau.
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - canh tranh cua nhung cong ((((van toan) or (dan than))) or (van tuan)) cau*.