Perhaps you should try some spelling variations:
sanh tri » thanh tri, dinh tri, minh tri
khoan he » khoa he, khoan ke, khoan le
he trong » he thong, he trung, le trong
sach tri » sach tai, sach tren, sach truc
so sanh » do sanh
tue cac » tu cac, tuc cac, te cac
so sach » bo sach, co sach, hoc sach
tri thi » tri tai, tai thi, thi thi
bach ha » bac ha, bich ha, bach khoa
sach ha » sach nha, sach han, sach xa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh tri tue cac khoan he trong ) OR ( so sach tri thi ((bach ha) OR (sach ha)) he trong ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sanh tri tue cac khoan he trong ) or ( so sach tri thi ((bach ha) OR (sach ha)) he trong ))~".
• Adding a wildcard symbol may retrieve word variants: (( so sanh tri tue cac khoan he trong ) or ( so sach tri thi ((bach ha) OR (sach ha)) he trong ))*.