Perhaps you should try some spelling variations:
ninh viet » sinh vien, anh viet
dinh viet » danh viet, trinh viet, sinh vien
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
dinh vi » dinh ve, dinh tri, dinh thi
cua tre » cua te, cuu tre, cua triet
te sac » te sach, te cac, te san
sac ky » cac ky, sai 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 sac ky sang ma hoa. hieu va pham duc va ((dinh vi) or (((dinh viet) OR (ninh viet)))) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky sang ma hoa. hieu va pham duc va ((dinh vi) OR (((dinh viet) OR (ninh viet)))) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky sang ma hoa. hieu va pham duc va ((dinh vi) or (((dinh viet) OR (ninh viet)))) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky sang ma hoa. hieu va pham duc va ((dinh vi) or (((dinh viet) OR (ninh viet)))) cua tre*.