Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
qua cac » cua cac
dao dai » dat dai, dao dan, tao dai
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang
tuc va » thuc va, truc va, duc va

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) OR (su sach)) y lang xa hoi. hieu qua cac ((tuc va) or (tuc xa)) dao dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y lang xa hoi. hieu qua cac ((tuc va) OR (tuc xa)) dao dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y lang xa hoi. hieu qua cac ((tuc va) or (tuc xa)) dao dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y lang xa hoi. hieu qua cac ((tuc va) or (tuc xa)) dao dai cua tre*.