Perhaps you should try some spelling variations:
chuyen hach » chuyen thanh, chuyen hang, thuyet hach
chuyen sach » chuyen san, quyen sach, truyen sach
cong lang » cong vang, cong luong, cong quang
lang toan » dang toan, lang thang, lang thanh
cua dung » cua dang, qua dung, cua rung
cua dong » chua dong, cua cong, cua dang
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 ((chuyen hach) OR (chuyen sach)) - canh tranh ((cua dung) or (cua dong)) cong lang toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chuyen hach) OR (chuyen sach)) - canh tranh ((cua dung) OR (cua dong)) cong lang toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chuyen hach) OR (chuyen sach)) - canh tranh ((cua dung) or (cua dong)) cong lang toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((chuyen hach) OR (chuyen sach)) - canh tranh ((cua dung) or (cua dong)) cong lang toan ban*.