Perhaps you should try some spelling variations:
khoan khap » khoanh khac, khoa kham, khoa khac
khap thong » phap thong, khau thong, khac thuong
sanh tri » thanh tri, dinh tri, minh tri
sach bac » sach bai, sach dao, sach xa
dac khoa » da khoa, dai khoa, dau khoa
so sanh » do sanh
tue cac » tu cac, tuc cac, te cac
te sach » toc sach
khoa he » hoa he, khoa hoc, khong he
bac le » ban le, mac le, cac le
le dac » le dan, le duc

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 cac khoan khap thong ) or ( te sach bac le dac khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh tri tue cac khoan khap thong ) OR ( te sach bac le dac khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sanh tri tue cac khoan khap thong ) or ( te sach bac le dac khoa he thong ))*.