Perhaps you should try some spelling variations:
khan thong » khap thong, khau thong, nhan thong
phau thong » phap thong, khau thong, phan thong
thai thuc » thai thuy, thai tuc, tham thuc
hanh khoa » hang khoa, anh khoa, hanh hoa
khoa phau » hoa phan, khoa kham, khoa than
nam thuc » nam thuoc, am thuc, nam thu
thuc hoc » phuc hoc, thu hoc, thuc uoc
hoc sach » hoc sinh, hoc cac, hoc anh
sach kho » bach khoa, sach dao, sach nha
kho khan » khoa kham, khoa than
cac thai » cac thoi, ca thai, cac thi
tu nam » su nam

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

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