Perhaps you should try some spelling variations:
coc thuc » hoc thuc, doc thuc, co thuc
thuc may » thuc day, truc may, phuc may
su sach » so sach, vu sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
tinh va » tich va, trinh van, trinh vat
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca 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)) ky lang xa hoi. ((hieu ve) or (hieu qua)) coc thuc may tinh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu bach)) ky lang xa hoi. ((hieu ve) OR (hieu qua)) coc thuc may tinh va cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu bach)) ky lang xa hoi. ((hieu ve) or (hieu qua)) coc thuc may tinh va cua tre*.