Perhaps you should try some spelling variations:
cdien sach » chieu sach, kien sach
dien sach » dien anh
nhan tang » nhan dang, nham tang, nhan lang
tang luan » dung luan
luan phan » luan van, luan hoan
phan hong » phan cong, pham hong, phan song
hong van » hoang van, thong van, phong van
van toan » van tuan, van tan, van thanh
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((dien sach) or (cdien sach)) - nhan tang luan phan hong van toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((dien sach) OR (cdien sach)) - nhan tang luan phan hong van toan ban*.