Perhaps you should try some spelling variations:
quyen tap » tuyen tap, luyen tap, quyen cap
cong cong » cong dong, trong cong, dung cong
cong dung » cuong dung, cong dong, cong luong
cac chu » cac thu, cac khu, ca chu
cac che » cac he, cac chien, cac chat
co ben » co benh, co ban, do ben
vat ky » vat ly, va ky, vat y

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

• Performing a fuzzy search may retrieve terms with similar spellings: quyen tap ((cac chu) OR (cac che)) đe co ben vat ky thi ((cong cong) or (cong dung))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: quyen tap ((cac chu) OR (cac che)) đe co ben vat ky thi ((cong cong) OR (cong dung)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "quyen tap ((cac chu) OR (cac che)) đe co ben vat ky thi ((cong cong) or (cong dung))".
• Adding a wildcard symbol may retrieve word variants: quyen tap ((cac chu) OR (cac che)) đe co ben vat ky thi ((cong cong) or (cong dung))*.