Perhaps you should try some spelling variations:
trinh vat » trinh luat, sinh vat, trinh han
trinh van » trinh han, trinh quan, trinh toan
dung cong » dung trong
chi sach » chinh sach, chieu sach, co sach
cong san » cong tac
san chan » san chang, dan chan, san chay
chan ban » can ban, chat ban, chan nan
doi chi » doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chi sach - hanh ((trinh vat) or (trinh van)) dung cong san chan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chi sach - hanh ((trinh vat) OR (trinh van)) dung cong san chan ban.
• Adding a wildcard symbol may retrieve word variants: doi chi sach - hanh ((trinh vat) or (trinh van)) dung cong san chan ban*.