Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
dung cong » dung trong
trang va » hang va
tran van » luan van
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap
lan van » luan van, lang van, tan van

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((((trang va) OR (tran van))) OR (lan van)) dung cong dan than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - hanh ((((trang va) OR (tran van))) or (lan van)) dung cong dan than cau~".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh ((((trang va) OR (tran van))) or (lan van)) dung cong dan than cau*.