Perhaps you should try some spelling variations:
chiet tach » chieu sach
thien hach » thien thanh, hien hanh
truong cao » truong dai
trung cao » trung cap, trung co, trung ca
han cong » phan cong, hang cong, hanh cong
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chiet tach) or (thien hach)) - thanh ((trung cao) OR (truong cao)) han cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chiet tach) OR (thien hach)) - thanh ((trung cao) OR (truong cao)) han cong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chiet tach) or (thien hach)) - thanh ((trung cao) OR (truong cao)) han cong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chiet tach) or (thien hach)) - thanh ((trung cao) OR (truong cao)) han cong dan toan cao*.