Perhaps you should try some spelling variations:
hien tach » thien hach, chiet tach, vien bach
trinh van » trinh han, trinh quan, trinh toan
dung cong » dung trong
trinh va » trinh vat, trinh ve, trinh vi
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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 ((trinh va) OR (trinh van)) dung cong dan than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien tach - hanh ((trinh va) OR (trinh van)) dung cong dan than cau".
• Adding a wildcard symbol may retrieve word variants: hoc hien tach - hanh ((trinh va) OR (trinh van)) dung cong dan than cau*.