Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
toc sach » hoc sach, doc sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
doi cua » dai cua, hoi cua
va danh » va dinh, va dan, va hanh
va tham » van tham, va cham, va thuat
sach tu » sach thu, cach tu, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, 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: toc sach tu ((nang xa) or (lang xa)) hoi. hieu va tham thuc ((va thanh) or (va danh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu ((nang xa) OR (lang xa)) hoi. hieu va tham thuc ((va thanh) OR (va danh)) doi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach tu ((nang xa) or (lang xa)) hoi. hieu va tham thuc ((va thanh) or (va danh)) doi cua tre*.