Perhaps you should try some spelling variations:
vang nguyen » dang nguyen, van nguyen, sang nguyen
nhung cong » dung cong, thong cong, hang cong
hien xanh » hien nhanh, chieu xanh, hien khanh
hien hanh » dieu hanh
truong va » truong dai, truong cao, truong dao
cong vang » cong lang, cong quang, cong ngang
trung va » trang va, trung ha, trung tam

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