Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cua tre » cua te, cua triet, dua tren
duc van » duc va, duc tan, duc manh
bao duc » dao duc, bao luc, cao duc
van bao » van ban, van dao
tang ho » tang cho, tung ho, tang ha
nang ho » nang hoc, nang co, nang cao
cuu tre » cau tren, cau treo
sach v » sach va, sach y, sach 2

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 v ((nang ho) OR (tang ho)) hoi. hieu van bao duc van thanh van ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v ((nang ho) OR (tang ho)) hoi. hieu van bao duc van thanh van ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v ((nang ho) OR (tang ho)) hoi. hieu van bao duc van thanh van ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach v ((nang ho) OR (tang ho)) hoi. hieu van bao duc van thanh van ((cua tre) or (cuu tre))*.