Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu lang » chieu sang, hieu quang, nhieu tang
trinh vat » trinh van, trinh luat, sinh vat
hang cong » hang nong, bang cong, thanh cong
dang cong » dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
tran ban » tranh ban, tran van, toan ban

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 lang - hanh trinh vat ((hang cong) OR (dang cong)) tan tran ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu lang - hanh trinh vat ((hang cong) OR (dang cong)) tan tran ban*".