Perhaps you should try some spelling variations:
thieu hach » thien hach, chieu sach, hieu cach
chiet tach » chieu sach
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
tranh cua » doanh cua, manh cua
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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

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