Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, theo sach
thanh tung » thanh cong
hieu cach » hieu cac, chieu sach, hieu ca
cua trong » cua truong, cua trung, qua trong
cong toan » cong tan, cong hoan, cong tuan
toan can » toan ban, toan cao, toan cau
can cau » van cau, ban cau, ca cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) or (hieu cach)) - ((thanh trung) or (thanh tung)) cua trong cong toan can cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (hieu cach)) - ((thanh trung) OR (thanh tung)) cua trong cong toan can cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) or (hieu cach)) - ((thanh trung) or (thanh tung)) cua trong cong toan can cau*.