Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thanh hai » thanh phan, thanh hoa, thanh san
vien dai » hien dai
va thanh » gia thanh, ban thanh, va tinh
dai thuc » dan thuc, dai thu, dai thua
cuc tre » duc tre, cuu tre, cuc thue
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
dan nam » van nam, dong nam, dinh nam
dang ma » dang mau, dang mam, dang mat
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: tu sach ky ((dang ma) or (dan nam)) hoi. hieu vien dai thuc va thanh hai ((cuc tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang ma) OR (dan nam)) hoi. hieu vien dai thuc va thanh hai ((cuc tre) OR (cua tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((dang ma) or (dan nam)) hoi. hieu vien dai thuc va thanh hai ((cuc tre) OR (cua tre))*".