Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
tang ma » mang may, tang van
cam luc » cam xuc, cau luc
van anh » van thanh, van minh
cua tre » cua te, cuu tre, cua triet
sinh 2 » sinh y
2 tang » 2 thang, 6 tang, 7 tang
ma hoi » mai hoi, xa hoi, ma hoa
va cua » va chua, via cua, ca cua
tuan » tran, luan, toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sinh 2 tang ma hoi. ((hieu qua) or (hieu quan)) cam luc ((van anh) OR (tuan anh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sinh 2 tang ma hoi. ((hieu qua) OR (hieu quan)) cam luc ((van anh) OR (tuan anh)) va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sinh 2 tang ma hoi. ((hieu qua) or (hieu quan)) cam luc ((van anh) OR (tuan anh)) va cua tre*".