Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
dinh viet » danh viet, trinh viet, sinh vien
toc sach » hoc sach, doc sach, thuoc sach
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
sach tu » sach thu, cach tu, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
tu xang » ty xang, tu lang, tu quang
qua tre » cua tre, quan tren, quan tri
ve cac » va cac, vien cac

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 tu xang ((xa hoi) or (mai hoi)). hieu ve cac duc va ((dinh viet) OR (ninh viet)) qua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu xang ((xa hoi) OR (mai hoi)). hieu ve cac duc va ((dinh viet) OR (ninh viet)) qua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu xang ((xa hoi) or (mai hoi)). hieu ve cac duc va ((dinh viet) OR (ninh viet)) qua tre*".