Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu sang » chieu sang, hieu lang, hieu quang
hanh tang » hanh trang, anh tang, hanh mang
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
toan tai » toan tap, doanh tai, toan ban
toan cao » toan ban, toan tap
tang va » trang va, tang van, thang va

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 sang - hanh tang va nhung cong dan ((toan tai) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - hanh tang va nhung cong dan ((toan tai) OR (toan cao)).
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - hanh tang va nhung cong dan ((toan tai) or (toan cao))*.