Perhaps you should try some spelling variations:
kham thong » khap thong, khau thong, pham thuong
khoan pho » khoan nhoi, khoan phai, khoan hoi
pho thong » he thong
trung cac » truong cac, trung cap, trong cac
khoa kham » kho khan, khoa than
sanh bai » sach bai, anh bai, san bai
bai thuc » bai thuoc, bao thuc, dai thuc
thuc cac » thuc cach, tuc cac, phuc cac
sach tai » sach bai, sach tham, sach dao
cac khoa » cac khoi, dac khoa, cao khoa
so sanh » do sanh
tu sach » thu sach, su sach, te sach

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 bai thuc cac khoan pho thong ) or ( tu sach tai trung cac khoa kham thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh bai thuc cac khoan pho thong ) OR ( tu sach tai trung cac khoa kham thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sanh bai thuc cac khoan pho thong ) or ( tu sach tai trung cac khoa kham thong ))*.