Perhaps you should try some spelling variations:
doi chiet » doi chieu, doi viet, doi chinh
trinh vat » trinh van, trinh luat, sinh vat
nang cong » nang song, dang cong, bang cong
trinh va » trinh van, trinh ve, trinh vi
cong van » cong vang, cong san, song van
van tuan » van quan, van ban, anh tuan
tuan cao » toan cao, juan cao, quang cao
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 chiet) or (doi chi)) tach - hanh ((trinh va) OR (trinh vat)) nang cong van tuan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chiet) OR (doi chi)) tach - hanh ((trinh va) OR (trinh vat)) nang cong van tuan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chiet) or (doi chi)) tach - hanh ((trinh va) OR (trinh vat)) nang cong van tuan cao".
• Adding a wildcard symbol may retrieve word variants: ((doi chiet) or (doi chi)) tach - hanh ((trinh va) OR (trinh vat)) nang cong van tuan cao*.