Perhaps you should try some spelling variations:
sach trinh » sach tranh, hanh trinh, sach kinh
trinh thuc » trinh tu, trinh thi
khoan pho » khoan nhoi, khoan phai, khoan hoi
thuc day » thuc dan, thuc vat
day khoa » da khoa, may khoa, dac khoa
sanh tri » thanh tri, dinh tri, minh tri
tri thuc » tri tue
thuc cac » thuc cach, tuc cac, phuc cac
te sach » toc sach
khoa he » hoa he, khoa hoc, khong he
so sanh » do sanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach trinh thuc day khoa he thong ) or ( so sanh tri thuc cac khoan pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trinh thuc day khoa he thong ) OR ( so sanh tri thuc cac khoan pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach trinh thuc day khoa he thong ) or ( so sanh tri thuc cac khoan pho thong ))*.