Perhaps you should try some spelling variations:
dinh toai » dinh toi, dinh tai, tinh toan
toai cua » thai cua, toan cua, loai cua
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
y lang » _ lang, tay lang, yen lang
tuc va » thuc va, truc va, duc va
o lang » hoa lang, hoi lang
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((y lang) OR (o lang)) xa hoi. hieu ve cam ((tuc va) or (tuc xa)) dinh toai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y lang) OR (o lang)) xa hoi. hieu ve cam ((tuc va) OR (tuc xa)) dinh toai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y lang) OR (o lang)) xa hoi. hieu ve cam ((tuc va) or (tuc xa)) dinh toai cua tre*".