Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
xanh di » vanh dai, xanh tai
danh di » danh du, danh dien, danh gia
qua cao » qua cac, qua ca, qua cai
cao suc » cao su, cao duc
cua tre » cua te, cuu tre, cua triet
y xang » ty xang
suc va » duc va, tuc va, luc va
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y xang ((x hoi) or (xa hoi)). hieu qua cao suc va ((danh di) OR (xanh di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y xang ((x hoi) OR (xa hoi)). hieu qua cao suc va ((danh di) OR (xanh di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y xang ((x hoi) or (xa hoi)). hieu qua cao suc va ((danh di) OR (xanh di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y xang ((x hoi) or (xa hoi)). hieu qua cao suc va ((danh di) OR (xanh di)) cua tre*.