Perhaps you should try some spelling variations:
thiet tach » chiet tach, thuat tach
thien hach » thien thanh, hien hanh
hanh tran » hanh trang, thanh tran, hanh tram
dung cong » dung trong
van thanh » ban thanh, van tuan
tran van » luan van
van dung » van dong, xay dung, tin dung
bai toan » bai tap

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: ho ((thiet tach) OR (thien hach)) - hanh tran van dung cong ((bai toan) OR (van thanh)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((thiet tach) OR (thien hach)) - hanh tran van dung cong ((bai toan) or (van thanh)) cau~".
• Adding a wildcard symbol may retrieve word variants: ho ((thiet tach) OR (thien hach)) - hanh tran van dung cong ((bai toan) or (van thanh)) cau*.