Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, cong tan
sach trinh » sach tranh, hanh trinh, sach kinh
sach tran » sach tranh, sach tren, vach tran
cong thai » cong hai, hong thai, cong tac
toc sach » hoc sach, doc sach, thuoc sach
trinh co » trinh do, trinh cong, trinh hoa
thu sach » tu sach, thuat sach, thuoc sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( toc sach trinh co khi đong luc ) or ( thu sach tran ((cong thai) OR (cong thanh)) đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( toc sach trinh co khi đong luc ) OR ( thu sach tran ((cong thai) OR (cong thanh)) đong luc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( toc sach trinh co khi đong luc ) or ( thu sach tran ((cong thai) OR (cong thanh)) đong luc ))".
• Adding a wildcard symbol may retrieve word variants: (( toc sach trinh co khi đong luc ) or ( thu sach tran ((cong thai) OR (cong thanh)) đong luc ))*.