Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ban tinh » ban thanh, quan tinh, ban hanh
tu sach » thu sach, su sach, te sach
tinh vi » trinh vi, tinh voi, tinh va
cuu ban » cuu van, cua ban, cuu san
cam cuu » cham cuu, cap cuu
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
y lang » o lang, tay lang, yen lang
_ lang » o lang, _ land
vi cua » vai cua, di cua

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 lang) OR (_ lang)) xa hoi. ((hieu ve) or (hieu van)) cam cuu ban tinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (_ lang)) xa hoi. ((hieu ve) OR (hieu van)) cam cuu ban tinh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) OR (_ lang)) xa hoi. ((hieu ve) or (hieu van)) cam cuu ban tinh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y lang) OR (_ lang)) xa hoi. ((hieu ve) or (hieu van)) cam cuu ban tinh vi cua tre*.