Perhaps you should try some spelling variations:
phau thong » phap thong, khau thong, phan thong
sach tren » sach tien, sach tranh
tren thuc » trien thuc, tron thuc, trinh thuc
hanh khoa » hang khoa, anh khoa, hanh hoa
truc toan » truc trang, duc toan, truc ban
khoa phau » hoa phan, khoa kham, khoa than
cach tri » cach thoi, cac tro, cach noi
tri truc » tri thuc, thi truc, tri thuoc
te sach » toc sach
khoa he » hoa he, khoa hoc, khong he
tu cach » tu cac

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 tren thuc hanh khoa he thong ) or ( tu cach tri truc toan khoa phau thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tren thuc hanh khoa he thong ) OR ( tu cach tri truc toan khoa phau thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach tren thuc hanh khoa he thong ) or ( tu cach tri truc toan khoa phau thong ))*.