Perhaps you should try some spelling variations:
thieu sach » chieu sach, hieu cach, theo sach
thien hach » thien thanh, hien hanh
trung tuan » trung thanh, tran tuan, truong thanh
nhung cong » dung cong, thong cong, hang cong
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
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: toc ((thieu sach) or (thien hach)) - hanh ((trung tuan) OR (trung tam)) nhung cong tan toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((thieu sach) OR (thien hach)) - hanh ((trung tuan) OR (trung tam)) nhung cong tan toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((thieu sach) or (thien hach)) - hanh ((trung tuan) OR (trung tam)) nhung cong tan toan ban".
• Adding a wildcard symbol may retrieve word variants: toc ((thieu sach) or (thien hach)) - hanh ((trung tuan) OR (trung tam)) nhung cong tan toan ban*.