Perhaps you should try some spelling variations:
tieu sach » chieu sach, dien sach, te sach
dung cong » dung trong
trung va » truong va, trang va, trung ha
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
tung va » tuong va, dung va, vung va

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo tieu sach - thanh ((tung va) OR (trung va)) dung cong dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo tieu sach - thanh ((tung va) OR (trung va)) dung cong dan toan cao*".