Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu tach » hieu cach, chiet tach, chieu sach
tang luan » dung luan
doc hieu » toc thieu, hoc thieu, hoc hien
hang cua » hang ca, huong cua, thong cua
mang cua » manh cua, dung cua, ban cua
cong tan » cong tac, cong san, cong thanh
tran tap » toan tap, tran tan, tran tuan

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 tach - hanh ((((hang cua) or (mang cua))) or (tang luan)) nhung cong tan tran tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tach - hanh ((((hang cua) OR (mang cua))) OR (tang luan)) nhung cong tan tran tap.
• Adding a wildcard symbol may retrieve word variants: doc hieu tach - hanh ((((hang cua) or (mang cua))) or (tang luan)) nhung cong tan tran tap*.