Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu bang » thu ban, thu hang, chu bang
vanh dai » van dai, lanh dao, van dao
vanh tai » van tai, hanh tai, anh tai
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, x ho
chuc » thuc, chu, chua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((thu bang) or (chuc nang)) x hoi. lieu va cam luc va ((vanh dai) OR (vanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((thu bang) OR (chuc nang)) x hoi. lieu va cam luc va ((vanh dai) OR (vanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((thu bang) or (chuc nang)) x hoi. lieu va cam luc va ((vanh dai) OR (vanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((thu bang) or (chuc nang)) x hoi. lieu va cam luc va ((vanh dai) OR (vanh tai)) cua tre*.