Perhaps you should try some spelling variations:
trinh vatn » trinh van, trinh han, trinh san
thong cong » trong cong, tong cong, thong thong
trinh vat » trinh van, trinh luat, sinh vat
cong toan » cong tan, cong hoan, cong tuan
doi chiu » doi chieu, doi chi, hoi chiu
toan ban » van ban
ban tu » van tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chiu trach - canh ((trinh vat) or (trinh vatn)) thong cong toan ban tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chiu trach - canh ((trinh vat) OR (trinh vatn)) thong cong toan ban tu.
• Adding a wildcard symbol may retrieve word variants: doi chiu trach - canh ((trinh vat) or (trinh vatn)) thong cong toan ban tu*.