Perhaps you should try some spelling variations:
gay thoi » may thoi, tay thoi, ngay tuoi
ky dang » ky nang, ky danh
hieu va » hieu qua
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 sai » tu bai, tu san, tu cai
sai ky » sac ky
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 sai ky dang ((gay thoi) or (xa hoi)). ((hieu va) or (lieu va)) cac hoc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ky dang ((gay thoi) OR (xa hoi)). ((hieu va) OR (lieu va)) cac hoc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sai ky dang ((gay thoi) or (xa hoi)). ((hieu va) or (lieu va)) cac hoc va hanh vi cua tre*.