Perhaps you should try some spelling variations:
phau thong » phap thong, phan thong, phan thuong
khau thong » khau thuong, khap thong, khau tong
sach tham » sach nha
tham thuc » nham thuc, pham thuc, tam thuc
thuc bach » truc bach, thuoc sach, thuc hanh
thuc cach » thuoc sach, truoc cach, thuc hanh
cach khoa » bach khoa, cac khoa, cac khoan
khoa phau » hoa phan, khoa kham, khoa than
sach dai » sach dao, sach bai, sach dat
dai thuc » dan thuc, dai thu, dai thua
tu sach » thu sach, su sach, te sach
bach ha » bac ha, bich ha, sach ha
ha khau » han khau, ha chau, nhap khau

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach tham thuc bach ha khau thong ) or ( tu sach dai thuc cach khoa phau thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tham thuc bach ha khau thong ) OR ( tu sach dai thuc cach khoa phau thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tham thuc bach ha khau thong ) or ( tu sach dai thuc cach khoa phau thong ))*.