Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
lang van » dang van, tang van, hoang van
dinh tai » dinh toai, dinh tri, dinh thi
van hoi » van hoa, van hoc, van hoe
hieu ve » hieu va, hieu van
va dinh » van dinh, va kinh, va tinh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
sach o » sach lo, sac o, sach y
ve cam » ve cham, ve cac, va cam
cam tu » cam thu, nam tu, dam tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach o) or (sach doi)) lang van hoi. hieu ve cam tu va dinh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach o) OR (sach doi)) lang van hoi. hieu ve cam tu va dinh tai cua tre*.