Perhaps you should try some spelling variations:
hieu cach » hieu cac, chieu sach, hieu ca
trung cua » truong cua, trung tuan, trung cap
tranh cua » doanh cua, manh cua
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu cach - hanh ((trung cua) or (tranh cua)) dung cong dan than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu cach - hanh ((trung cua) OR (tranh cua)) dung cong dan than cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu cach - hanh ((trung cua) or (tranh cua)) dung cong dan than cau*.