Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
dinh viet » danh viet, trinh viet, sinh vien
sach tru » sach truc, sach thu, sach tu
te sach » toc sach
cac dac » cac dan, cac dai, cac bac
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
dac va » duc va, day va, dat va
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: te sach tru ((nang ma) OR (tang ma)) hoa. hieu ve cac dac va ((dinh viet) or (ninh viet)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tru ((nang ma) OR (tang ma)) hoa. hieu ve cac dac va ((dinh viet) OR (ninh viet)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tru ((nang ma) OR (tang ma)) hoa. hieu ve cac dac va ((dinh viet) or (ninh viet)) cua tre*".