Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, cau phuc
can thuc » dan thuc, van thuc, cay thuc
vat hanh » vat thanh, van hanh, va hanh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
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: tu ((sach ky) or (cac ky)) nang xa hoi. hieu va ((cau thuc) OR (can thuc)) vat hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (cac ky)) nang xa hoi. hieu va ((cau thuc) OR (can thuc)) vat hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (cac ky)) nang xa hoi. hieu va ((cau thuc) OR (can thuc)) vat hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (cac ky)) nang xa hoi. hieu va ((cau thuc) OR (can thuc)) vat hanh vi cua tre*.