Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
sach tren » sach tien, sach tranh
cach thuc » anh thuc, cac thu
thuc bach » truc bach, thuc cach, thuc hanh
pho thong » he thong
sach tri » sach tai, sach truc, sach bai
khoa pho » khoa phu, khoa khoa, khoa phau

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 tri) or (((sach tren) or (cach thuc)))) ((thuc bach) or (thuoc sach)) khoa pho thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tri) OR (((sach tren) OR (cach thuc)))) ((thuc bach) OR (thuoc sach)) khoa pho thong.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tri) or (((sach tren) or (cach thuc)))) ((thuc bach) or (thuoc sach)) khoa pho thong*.