Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nang cong » nang song, dang cong, bang cong
cong cong » cong dong, trong cong, dung cong
hieu van » hieu va, thien van, lieu va
pho nang » ho nang, cho nang, pho mang
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((chieu sach) OR (hieu van)) - thanh pho nang cong cong dan than tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((chieu sach) OR (hieu van)) - thanh pho nang cong cong dan than tap*".