Perhaps you should try some spelling variations:
cau thuc » cau truc, can thuc, cau phuc
hanh tai » thanh tai, hang tai, han tai
vat hanh » vat thanh, van hanh, va hanh
cuu thuc » cuu tac
tay thai » lay thai, toc thai, y thai
so sach » so sanh, bo sach, co sach
tai cua » thai cua, tai cuc, tri cua
hieu ve » hieu va, hieu van
sach ly » sach y, sach lo, sach ty
tao hoi » tao khoi, tao boi, tay hoi
ly hang » ly quang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly hang ((tao hoi) or (tay thai)). hieu ve ((cau thuc) or (cuu thuc)) vat hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly hang ((tao hoi) OR (tay thai)). hieu ve ((cau thuc) OR (cuu thuc)) vat hanh tai cua te.
• Adding a wildcard symbol may retrieve word variants: so sach ly hang ((tao hoi) or (tay thai)). hieu ve ((cau thuc) or (cuu thuc)) vat hanh tai cua te*.