Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
tang luan » dung luan
trong van » trong cac
thong dan » thong van, tuong dan, thong den
doc hieu » toc thieu, hoc thieu, hoc hien
dan chan » dan gian, dan ca, van chat
chan ta » chan tha, nhan tai, nhan tao

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu xanh - hanh ((tang luan) or (trong van)) thong thong dan chan ta~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((tang luan) OR (trong van)) thong thong dan chan ta.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((tang luan) or (trong van)) thong thong dan chan ta*.