Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
thanh tung » thanh cong
hieu xanh » chieu xanh, hieu manh, dieu hanh
cong nang » cong ngang, cong lang, cong nong
nang phat » nang suat, van phat
va hang » van hang, va nang, va hanh
va lang » va nang, hoa lang
phat tu » phan tu, pham tu, phap tu

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 xanh) or (hieu nganh)) - thanh tung ((va hang) OR (va lang)) cong nang phat tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (hieu nganh)) - thanh tung ((va hang) OR (va lang)) cong nang phat tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) or (hieu nganh)) - thanh tung ((va hang) OR (va lang)) cong nang phat tu".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (hieu nganh)) - thanh tung ((va hang) OR (va lang)) cong nang phat tu*.