Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hien xanh » hien hanh, hien nhanh, chieu xanh
han huong » han thuong, han phuong, van huong
ban huong » bang phuong, ban hang, anh huong
anh tang » anh bang, anh dang, anh nang
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

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 - ((anh tang) or (hanh trinh)) luan ((han huong) OR (ban huong)) dan than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - ((anh tang) OR (hanh trinh)) luan ((han huong) OR (ban huong)) dan than tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - ((anh tang) or (hanh trinh)) luan ((han huong) OR (ban huong)) dan than tap".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - ((anh tang) or (hanh trinh)) luan ((han huong) OR (ban huong)) dan than tap*.