Perhaps you should try some spelling variations:
thieu hach » thien hach, chieu sach, hieu cach
cong quan » cuong quan, cong quang, tong quan
quan dung » quang dung, quan duong, qua dung
dung cong » dung trong
cong tan » cong tac, cong san, cong thanh
phan van » pham van, thanh van, luan van
phan lap » phan dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc thieu hach - thanh cong quan dung cong tan ((phan van) OR (phan lap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc thieu hach - thanh cong quan dung cong tan ((phan van) OR (phan lap))*".