Perhaps you should try some spelling variations:
quyen tap » tuyen tap, luyen tap, quyen cap
tac dung » sach dung, xay dung, van dung
cac chu » cac thu, cac che, cac cau
cac khu » cac thu, cac khoi, cac kieu
ban vat » bang vat, ben vat, ban va
ca chu » cua chu, ca chua, can chu
vat y » vat ly, vat _

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 (ca chu))) or (cac khu)) đe co ban vat y ((tac dung) or (tin dung)) cong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: quyen tap ((((cac chu) OR (ca chu))) OR (cac khu)) đe co ban vat y ((tac dung) OR (tin dung)) cong.
• The words AND, OR and NOT may confuse the search; try adding quotes: "quyen tap ((((cac chu) OR (ca chu))) or (cac khu)) đe co ban vat y ((tac dung) or (tin dung)) cong".
• Adding a wildcard symbol may retrieve word variants: quyen tap ((((cac chu) OR (ca chu))) or (cac khu)) đe co ban vat y ((tac dung) or (tin dung)) cong*.