Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
hieu van » hieu va, thien van, lieu va
mang xa » lang xa, mang may, dang xay
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
cau tuc » cau truc, cau tu, cau luc
xa hanh » xa thanh, xa khanh, va hanh
cuu tre » cua tre, cau tren
tu sach » thu sach, su sach, te sach

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