Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thu nang » thi nang, thu hang, thu bang
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham xuc » tham nuoc, tham thuc, pham duc
hanh hai » thanh hai, nhanh hai, hang hai
cao hoi » cau hoi, co hoi, cao hoc
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) thu nang cao hoi. hieu van tham xuc va hanh hai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) thu nang cao hoi. hieu van tham xuc va hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) thu nang cao hoi. hieu van tham xuc va hanh hai cua tre*.