Perhaps you should try some spelling variations:
sanh tri » thanh tri, dinh tri, minh tri
tue cach » tu cach, thuc cach, ve cach
cach hoa » cach hoan, cach hoc, bach hoa
he trong » he thong, he trung, le trong
hoc sach » hoc sinh, hoc cac, hoc anh
tren thi » trien thi, trieu thi, trinh thi
so sanh » do sanh
bach ha » bac ha, bich ha, sach ha
ha he » ha le, va he

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

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