Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
dang xa » dang xay, lang xa, dang ha
dong ha » dong hoa, dong va, dong hoc
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
duc ban » duc van, dua ban, duc man
tinh vi » trinh vi, tinh voi, tinh va
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

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