Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
viet cua » viec cua, viet ca, viet qua
sach ty » sach y, sach thu, xach tay
va ninh » van ninh, va kinh, va tinh
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
sach tu » sach thu, cach tu, sach uu
ma hoi » xa hoi, ma hoa, me hoi
ve cac » va cac, vien cac
dan va » doan va, dan ca, ban va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) or (sach tu)) xang ((ma hoi) OR (mai hoi)). hieu ve cac dan va ninh viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach tu)) xang ((ma hoi) OR (mai hoi)). hieu ve cac dan va ninh viet cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach tu)) xang ((ma hoi) OR (mai hoi)). hieu ve cac dan va ninh viet cua tre*".