Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
te sach » toc sach
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
nam tu » nam thu
vi cua » vai cua, di cua

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) or (su sach)) ky nang x ho. hieu van ((nam tu) OR (nam thuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (su sach)) ky nang x ho. hieu van ((nam tu) OR (nam thuc)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (su sach)) ky nang x ho. hieu van ((nam tu) OR (nam thuc)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (su sach)) ky nang x ho. hieu van ((nam tu) OR (nam thuc)) va hanh vi cua tre*.