Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
ban anh » ban hanh, ban banh, ban danh
nam xuc » cam xuc, nam xua, nam duoc
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
anh vi » hanh vi, anh va, anh ve
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: ((su sach) or (vu bach)) ty lang xa hoi. hieu van ((nam xuc) OR (nam thuc)) ban anh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu bach)) ty lang xa hoi. hieu van ((nam xuc) OR (nam thuc)) ban anh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu bach)) ty lang xa hoi. hieu van ((nam xuc) OR (nam thuc)) ban anh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu bach)) ty lang xa hoi. hieu van ((nam xuc) OR (nam thuc)) ban anh vi cua tre*.