Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
tinh va » tich va, trinh van, trinh vat
tinh vi » trinh vi, tinh voi, dinh vi
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
nang ho » nang hoc, nang co, tang ho
dai va » mai va
ho hoi » hoc hoi, hoa hoi, hoi hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ho hoi. ((hieu vien) or (hieu hien)) can dai va ((tinh vi) OR (tinh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ho hoi. ((hieu vien) OR (hieu hien)) can dai va ((tinh vi) OR (tinh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ho hoi. ((hieu vien) or (hieu hien)) can dai va ((tinh vi) OR (tinh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ho hoi. ((hieu vien) or (hieu hien)) can dai va ((tinh vi) OR (tinh va)) cua tre*.