Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh tai » thanh hai, thanh toan, doanh tai
chat huu » pham huu
hieu van » hieu va, thien van, lieu va
van chat » cao chat
cua tre » cua te, cua triet, dua tren
huu ban » huu bang, huu han, cuu ban
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo

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 van chat huu ban thanh tai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (cac ky)) nang xa hoi. hieu van chat huu ban thanh tai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (cac ky)) nang xa hoi. hieu van chat huu ban thanh tai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (cac ky)) nang xa hoi. hieu van chat huu ban thanh tai ((cua tre) OR (cuu tre))*.