Perhaps you should try some spelling variations:
dinh viet » danh viet, trinh viet, sinh vien
ninh viet » sinh vien, anh viet
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet

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 nang ma hoa. ((hieu ve) OR (hieu va)) cac duc va ((dinh viet) or (ninh viet)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang ma hoa. ((hieu ve) OR (hieu va)) cac duc va ((dinh viet) OR (ninh viet)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang ma hoa. ((hieu ve) OR (hieu va)) cac duc va ((dinh viet) or (ninh viet)) cua tre*".