Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
toc sach » hoc sach, doc sach, thuoc sach
hanh hoi » hanh thoi, hanh noi, hanh hoa
mang xa » lang xa, mang may, dang xay
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
nang xa » lang xa, nang ma, ang xa
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hoi cua » hoi chuc
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ly ((((nang xa) OR (mang xa))) or (nang x)) hoi. hieu ve tham thuc va hanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ly ((((nang xa) OR (mang xa))) OR (nang x)) hoi. hieu ve tham thuc va hanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ly ((((nang xa) OR (mang xa))) or (nang x)) hoi. hieu ve tham thuc va hanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ly ((((nang xa) OR (mang xa))) or (nang x)) hoi. hieu ve tham thuc va hanh hoi cua tre*.