Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
cham hoc » cham soc, chat hoc, cham hoi
hieu van » thien van, lieu va, hieu ve
cuu tre » cua tre, cau tren, cau treo
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky lang xa hoi. ((hieu van) OR (hieu va)) cham hoc va danh vi ((cuu tre) OR (cau theo))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky lang xa hoi. ((hieu van) OR (hieu va)) cham hoc va danh vi ((cuu tre) or (cau theo))~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky lang xa hoi. ((hieu van) OR (hieu va)) cham hoc va danh vi ((cuu tre) or (cau theo))*.