Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
thanh doi » thanh loi, thanh moi, thanh do
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, nam thu, nam tu
toc sac » toc sach, toc san, hoc sach
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky nang xa hoi. hieu van ((nam thuc) or (am thuc)) day thanh doi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky nang xa hoi. hieu van ((nam thuc) OR (am thuc)) day thanh doi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky nang xa hoi. hieu van ((nam thuc) or (am thuc)) day thanh doi ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sac ky nang xa hoi. hieu van ((nam thuc) or (am thuc)) day thanh doi ((cua tre) OR (cuu tre))*.