Perhaps you should try some spelling variations:
nang thong » nang thuong, mang thong, nang trong
cdien sach » chieu sach, kien sach
dien sach » dien anh
nhan lang » nhanh lang, nhan dang, nhon lang
lang luan » tang luan, hang luan, bang luan
luan nang » luan van, van nang, luan san
thong van » trong van, thong va, thong quan
van tan » van tuan, van ban, van tai
tan tap » toan tap, han tap, tan tat

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 lang luan nang thong van tan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((dien sach) OR (cdien sach)) - nhan lang luan nang thong van tan tap*.