Perhaps you should try some spelling variations:
doanh cua » doanh luan
va triet » va thiet, va trien, ve triet
doanh va » doan va, doanh tai, hanh va
hieu ve » hieu va, hieu van
cac che » cac he, cac chien, cac chat
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach
ve cac » va cac, vien cac
y nang » ky nang, ly nang, v 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 y nang xa hoi. hieu ve cac che va ((doanh va) OR (doanh cua)) ((cua tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu ve cac che va ((doanh va) OR (doanh cua)) ((cua tre) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu ve cac che va ((doanh va) OR (doanh cua)) ((cua tre) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu ve cac che va ((doanh va) OR (doanh cua)) ((cua tre) or (va triet))*.