Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
doanh van » doan van, doanh va, doanh ban
vien cac » vien bach, vien dai, vien da
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
van cuu » van cau, van chu, van cu
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
lo van » vo van, do van, ho van
so van » su van, vo van

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 y nang xa hoi. hieu vien cac ((((lo van) OR (so van))) or (le van)) doanh van cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu vien cac ((((lo van) OR (so van))) OR (le van)) doanh van cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu vien cac ((((lo van) OR (so van))) or (le van)) doanh van cuu tre*".