Perhaps you should try some spelling variations:
doanh luan » doanh nhan
tu sach » thu sach, su sach, te sach
cac tuc » cac toc, cac tu, cac tac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
tuc va » thuc va, truc va, tuc xa
me hoi » le hoi
v nang » va nang, vu nang, van nang

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 v nang ((me hoi) or (ma hoa)). hieu va cac tuc va ((doanh cua) OR (doanh luan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang ((me hoi) OR (ma hoa)). hieu va cac tuc va ((doanh cua) OR (doanh luan)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang ((me hoi) or (ma hoa)). hieu va cac tuc va ((doanh cua) OR (doanh luan)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang ((me hoi) or (ma hoa)). hieu va cac tuc va ((doanh cua) OR (doanh luan)) cua tre*.