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
so sach » so sanh, bo sach, co sach
luc van » luoc van, luu van, duc van
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach v nang o hai. hieu vien cac ((luc van) or (duc tan)) hanh thai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang o hai. hieu vien cac ((luc van) OR (duc tan)) hanh thai cua te.
• Adding a wildcard symbol may retrieve word variants: so sach v nang o hai. hieu vien cac ((luc van) or (duc tan)) hanh thai cua te*.