Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hanh may » hanh ma, hanh mau, hanh ngay
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
dang ma » dang mau, dang mam, dang mat
may duc » mai duc, my duc
duc tre » duoc tren, duc tien
tac va » tac da, tuc va, tac ha
tac xa » tuc xa, tac da

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 hoa. hieu vien cac ((tac va) or (tac xa)) hanh may duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ma hoa. hieu vien cac ((tac va) OR (tac xa)) hanh may duc tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ma hoa. hieu vien cac ((tac va) or (tac xa)) hanh may duc tre*.