Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien dai » hien dai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky mang » ky nang, ke mang, ky dang
may hoa » may khoa, ma hoa, day hoa
dai tuc » dai thuc, dai truc, dao tuc
tuc may » truc may, tu may, tuc xay
di cua » doi cua, de cua, do cua

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 mang may hoa. hieu vien dai tuc may tinh ((di cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky mang may hoa. hieu vien dai tuc may tinh ((di cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky mang may hoa. hieu vien dai tuc may tinh ((di cua) or (dai cua)) tre*.