Perhaps you should try some spelling variations:
chiet tach » chieu sach
trong quan » thong quan, thong quang, luong quan
hieu lang » chieu sang, hieu quang, nhieu tang
tong quan » thong quan, tong luan, luong quan
trong van » trong cac
van toan » van tuan, van tan, van thanh
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu lang) or (chiet tach)) - hanh ((trong quan) OR (tong quan)) dung trong van toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu lang) OR (chiet tach)) - hanh ((trong quan) OR (tong quan)) dung trong van toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu lang) or (chiet tach)) - hanh ((trong quan) OR (tong quan)) dung trong van toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) or (chiet tach)) - hanh ((trong quan) OR (tong quan)) dung trong van toan ban*.