Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang xa hoi. ((hieu ve) or (hieu va)) cau thuc ((va hanh) OR (va danh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. ((hieu ve) OR (hieu va)) cau thuc ((va hanh) OR (va danh)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. ((hieu ve) or (hieu va)) cau thuc ((va hanh) OR (va danh)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. ((hieu ve) or (hieu va)) cau thuc ((va hanh) OR (va danh)) vai cua tre*.