Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh thai » nhanh thai, hinh thai, hanh tai
vien cac » vien bach, vien dai, vien da
thai cua » than cua, tai cuc, tri cua
thu sach » thuat sach, thuoc sach, thu hoach
luc van » luoc van, duc van, luc va
luu van » cuu van, luan van, luu hanh
tu sach » su sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ma hoi. hieu vien cac ((luc van) OR (luu van)) hanh thai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang ma hoi. hieu vien cac ((luc van) OR (luu van)) hanh thai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ma hoi. hieu vien cac ((luc van) OR (luu van)) hanh thai cua tre*.