Perhaps you should try some spelling variations:
khau thong » khau thuong, khap thong, khau tong
khoa khau » khoa kham, khoa phau, khoa chau
khoan hoi » khoan nhoi, khoa hoi, khoa hoc
hoi thong » hoi thuong, hoi trong, hoa thong
hanh dan » thanh dan, hanh san, canh dan
dan thuc » dan toc, am thuc
thuc cac » thuc cach, tuc cac, phuc cac
cac khoa » cac khoi, dac khoa, cao khoa
sach bai » sach dao, cac bai, sach xa
tu hanh » du hanh, lu hanh, thuc hanh
su sach » so sach, vu sach
bai hoc » dai hoc
hoc cac » hoc cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu hanh dan thuc cac khoa khau thong ) or ( su sach bai hoc cac khoan hoi thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hanh dan thuc cac khoa khau thong ) OR ( su sach bai hoc cac khoan hoi thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu hanh dan thuc cac khoa khau thong ) or ( su sach bai hoc cac khoan hoi thong ))*.