Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
hien xanh » hien hanh, hien nhanh, chieu xanh
trinh vat » trinh van, trinh luat, sinh vat
dung cong » dung trong
trinh va » trinh van, trinh ve, trinh vi
dan chan » dan gian, dan ca, van chat
chan ban » can ban, chat ban, chan nan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - hanh ((trinh va) OR (trinh vat)) ((nhung cong) or (dung cong)) dan chan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((trinh va) OR (trinh vat)) ((nhung cong) OR (dung cong)) dan chan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - hanh ((trinh va) OR (trinh vat)) ((nhung cong) or (dung cong)) dan chan ban".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh ((trinh va) OR (trinh vat)) ((nhung cong) or (dung cong)) dan chan ban*.