Perhaps you should try some spelling variations:
chiet tach » chieu sach
doi chiet » doi chieu, doi chi, doi viet
trinh vat » trinh luat, sinh vat, trinh han
trinh van » trinh han, trinh quan, trinh toan
dung cong » dung trong
san chang » ban hang, dan chan, van khang
chang ban » hang ban, chang ran, chang nang
cong san » cong tac

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

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