Perhaps you should try some spelling variations:
hieu manh » chieu xanh, hieu nganh, dieu hanh
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cach ban » cac ban, cach ben, cach van
cach bao » cach nao, sach bao, cach giao
cua dung » cua dang, cua dong, qua dung
san phan » san pham, van phan, dan phan
sat phan » sat nhan, vat phan, xuat phan

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 manh - ((cach ban) or (cach bao)) cua dung cong ((san phan) or (sat phan)) lap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu manh - ((cach ban) OR (cach bao)) cua dung cong ((san phan) OR (sat phan)) lap.
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - ((cach ban) or (cach bao)) cua dung cong ((san phan) or (sat phan)) lap*.