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