Perhaps you should try some spelling variations:
doanh sang » doanh quang, doanh ban, doanh van
hieu van » hieu va, thien van, lieu va
sang cua » mang cua, song cua, hang cua
va doanh » van doanh, vay doanh, va danh
cham cuu » cap cuu, chat cua
tu sach » thu sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
cuu va » cuu van, cuu ve
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) OR (su sach)) y nang xa hoi. ((hieu ve) or (hieu van)) cham cuu va doanh sang cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang xa hoi. ((hieu ve) OR (hieu van)) cham cuu va doanh sang cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang xa hoi. ((hieu ve) or (hieu van)) cham cuu va doanh sang cua tre*".