Perhaps you should try some spelling variations:
trinh van » trinh han, trinh quan, trinh toan
hang cong » dang cong, hang nong, bang cong
toc hieu » toc thieu, doc hieu, hoc thieu
trinh va » trinh vat, trinh ve, trinh vi
cong tac » cong ty
tac phan » tac pham, tai phan, tac phat
phan dau » phan tu, hang dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc hieu qua - hanh ((trinh va) OR (trinh van)) hang cong tac phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc hieu qua - hanh ((trinh va) OR (trinh van)) hang cong tac phan dau".
• Adding a wildcard symbol may retrieve word variants: toc hieu qua - hanh ((trinh va) OR (trinh van)) hang cong tac phan dau*.