Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
hoi cua » hoi chuc
va hanh » van hanh, va danh, ban hanh
ve tham » va tham, ve cham, vi tham
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va, hieu van
nang xa » lang xa, nang ma, mang xa
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: te sach ly ((nang xa) or (nang x)) hoi. hieu ve tham thuc ((va hanh) OR (va thanh)) hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ly ((nang xa) OR (nang x)) hoi. hieu ve tham thuc ((va hanh) OR (va thanh)) hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ly ((nang xa) or (nang x)) hoi. hieu ve tham thuc ((va hanh) OR (va thanh)) hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ly ((nang xa) or (nang x)) hoi. hieu ve tham thuc ((va hanh) OR (va thanh)) hoi cua tre*.