Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
dinh viet » danh viet, trinh viet, sinh vien
cac dau » cac dan, cac du, cac dai
sach ty » sach y, sach thu, xach tay
hieu ve » hieu va, hieu van
xang ma » tang ma, nang ma, sang ma
sach tu » sach thu, cach tu, sach uu
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
dau va » dau ve, lau va

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

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