Perhaps you should try some spelling variations:
cuu tre » cau tren, cau treo
cac hoc » cach hoc, cac hop, bac hoc
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cua tre » cua te, cua triet, dua tren
cac loc » cac lop, cac toc, cac nuoc
va hanh » van hanh, va thanh, va danh
tu sac » tu sach, tu cac, tu san
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: tu sac ky lang xa hoi. hieu ve ((cac loc) OR (cac hoc)) va hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky lang xa hoi. hieu ve ((cac loc) OR (cac hoc)) va hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky lang xa hoi. hieu ve ((cac loc) OR (cac hoc)) va hanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky lang xa hoi. hieu ve ((cac loc) OR (cac hoc)) va hanh vi ((cua tre) or (cuu tre))*.