Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
toc sach » hoc sach, doc sach, thuoc sach
sach ky » sac ky, sach y, sach ty
van hoi » van hoa, van hoc, van loi
van hoe » van hoa, van hoc, van hieu
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua

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 ky nang ((van hoi) or (van hoe)). hieu va tham thuc va hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ((van hoi) OR (van hoe)). hieu va tham thuc va hanh de cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ((van hoi) or (van hoe)). hieu va tham thuc va hanh de cua tre*.