Perhaps you should try some spelling variations:
thong danh » thong dan, thong lanh, trong danh
hieu lang » chieu sang, hieu quang, nhieu tang
danh toan » manh toan, anh toan, dan toan
trang va » hang va
tran van » luan van
toan ban » van ban
ho hieu » ho chieu, hoi hieu, nho hieu

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: ho hieu lang - hanh ((trang va) OR (tran van)) thong thong danh toan ban~.
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((trang va) or (tran van)) thong thong danh toan ban*.