Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
tinh vi » trinh vi, tinh voi, tinh va
cuc ban » cac ban, cuu ban, duc ban
ve pham » vi pham, v pham, ve phan
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
dang ha » dong ha, dung ha, lang ha
dang xa » dang xay, lang xa, dang 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.

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