Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
hieu lang » chieu sang, hieu quang, nhieu tang
hang cong » dang cong, hang nong, bang cong
cong tan » cong tac, cong san, cong thanh
bang cau » hang cau, bang cac, nang cao
he hieu » he nhieu, he dieu, de hieu
ban cau » ban can, van cau, ban dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: he hieu lang - canh ((trinh quan) or (sinh vat)) hang cong tan ((ban cau) OR (bang cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: he hieu lang - canh ((trinh quan) OR (sinh vat)) hang cong tan ((ban cau) OR (bang cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "he hieu lang - canh ((trinh quan) or (sinh vat)) hang cong tan ((ban cau) OR (bang cau))".
• Adding a wildcard symbol may retrieve word variants: he hieu lang - canh ((trinh quan) or (sinh vat)) hang cong tan ((ban cau) OR (bang cau))*.