Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
sach thu » sach thue, sach thieu, sach tham
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
te sach » toc sach
cua tre » cua te, cua triet, dua tren
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
cuu tre » cau tren, cau treo
hang x » hoang xa, chang xu, hang nxb

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