Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
vat hanh » vat thanh, van hanh, nhat hanh
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
va cau » van cau, va cac, va dau
vi cua » vai cua, di cua

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

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