Perhaps you should try some spelling variations:
ban thanh » ban hang
thu sach » tu sach, thuat sach, thuoc sach
tay lang » tai lang, tay tang, tay quang
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
vai cuu » vai cua
van bao » van ban, van dao
bao duc » dao duc, bao luc, cao duc
cuu tre » cua tre, cau tren, cau treo
y lang » o lang, _ lang, yen lang

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 lang) OR (tay lang)) xa hoi. hieu van bao duc ((ban thanh) or (ban hanh)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((y lang) OR (tay lang)) xa hoi. hieu van bao duc ((ban thanh) OR (ban hanh)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((y lang) OR (tay lang)) xa hoi. hieu van bao duc ((ban thanh) or (ban hanh)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((y lang) OR (tay lang)) xa hoi. hieu van bao duc ((ban thanh) or (ban hanh)) vai cuu tre*.