Perhaps you should try some spelling variations:
nam duoc » nam thuoc, da duoc, nam moc
dat duoc » dat nuoc, da duoc, luat duoc
dinh tri » chinh tri
tang ma » mang may, tang van
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
te sai » te tai, te bai, te lai
sai ky » sac ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sai ky ((nang cao) or (tang ma)) hoi. hieu qua ((nam duoc) OR (dat duoc)) va dinh tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sai ky ((nang cao) OR (tang ma)) hoi. hieu qua ((nam duoc) OR (dat duoc)) va dinh tri cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sai ky ((nang cao) or (tang ma)) hoi. hieu qua ((nam duoc) OR (dat duoc)) va dinh tri cua tre".
• Adding a wildcard symbol may retrieve word variants: te sai ky ((nang cao) or (tang ma)) hoi. hieu qua ((nam duoc) OR (dat duoc)) va dinh tri cua tre*.