Perhaps you should try some spelling variations:
thong trong » thuong trong, thong thong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
han thong » han thuong, hang thong, nhan thong
trong van » trong cac
hoc hieu » hoc thieu, hoc hien, doc hieu
van than » van thanh, van thang, van tuan
than cau » toan cau, phan cau, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - ((canh tranh) or (hanh chinh)) han thong trong van than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - ((canh tranh) OR (hanh chinh)) han thong trong van than cau*.