Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
toc sach » hoc sach, doc sach, thuoc sach
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (toc sach)) ky nang x hoi. hieu ve tham thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky nang x hoi. hieu ve tham thuc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky nang x hoi. hieu ve tham thuc va hanh vi cua tre*.