Perhaps you should try some spelling variations:
hien tach » thien hach, chiet tach, vien bach
trung lap » trung cap, truong lam, truong lop
dung cong » dung trong
trung ap » trung cap, trung tam, trung dai
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cau » 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 hien tach - hanh ((trung ap) or (trung lap)) dung cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien tach - hanh ((trung ap) OR (trung lap)) dung cong dan toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc hien tach - hanh ((trung ap) or (trung lap)) dung cong dan toan cau*.