Perhaps you should try some spelling variations:
viet tach » viet sach, viet tech, viet thanh
truong va » truong dai, truong cao, truong dao
trang va » tran van, hang va
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
than cau » toan cau, phan cau, than cap
phap » phan, pham

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

• Performing a fuzzy search may retrieve terms with similar spellings: phap viet tach - thanh ((truong va) or (trang va)) dung ((cong dan) OR (cong san)) than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: phap viet tach - thanh ((truong va) OR (trang va)) dung ((cong dan) OR (cong san)) than cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "phap viet tach - thanh ((truong va) or (trang va)) dung ((cong dan) OR (cong san)) than cau".
• Adding a wildcard symbol may retrieve word variants: phap viet tach - thanh ((truong va) or (trang va)) dung ((cong dan) OR (cong san)) than cau*.