Perhaps you should try some spelling variations:
doanh cua » doanh luan
tu sach » thu sach, su sach, te sach
danh ca » dan ca, danh cho, danh gia
cac tru » ca tru, cac tro, cac thu
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
tru va » truc va, tu va, trung va
me hoi » le hoi

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