Perhaps you should try some spelling variations:
anh thuc » am thuc, dan thuc, anh tu
cac thoi » cac toi, cac hop, cac tro
cua tre » cua te, cuu tre, cua triet
doan vi » doan va, don vi, doan thi
nang ho » nang hoc, nang co, tang ho
va doan » va doanh, van doan, va dan
hieu ve » hieu va, hieu van
vi cua » vai cua, di cua
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
nang o » nang co, nang ro, nang x

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 ((nang o) OR (nang ho)) hoi. hieu ve ((cac thoi) or (anh thuc)) va doan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang o) OR (nang ho)) hoi. hieu ve ((cac thoi) OR (anh thuc)) va doan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang o) OR (nang ho)) hoi. hieu ve ((cac thoi) or (anh thuc)) va doan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang o) OR (nang ho)) hoi. hieu ve ((cac thoi) or (anh thuc)) va doan vi cua tre*.