Perhaps you should try some spelling variations:
kham thong » khap thong, khau thong, pham thuong
khoan phai » khong phai, khoa phau, khoan hoi
phai thong » phap thong, phai tuong, phan thong
khoa kham » kho khan, khoa than
cach hoc » cach thuc, cach thoi, dich hoc
hoc hieu » hoc thieu, hoc hien, doc hieu
hieu cac » hieu luc, hieu va, hieu van
cac khoa » cac khoi, dac khoa, cao khoa
sach tri » sach tai, sach tren, sach bai
tu cach » tu cac
te sach » toc sach
tri tuc » tri thuc, tri tue, tri tac
tuc cac » tu cac, tich cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu cach hoc hieu cac khoa kham thong ) or ( te sach tri tuc cac khoan phai thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu cach hoc hieu cac khoa kham thong ) OR ( te sach tri tuc cac khoan phai thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu cach hoc hieu cac khoa kham thong ) or ( te sach tri tuc cac khoan phai thong ))*.