Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hoc thien » hoc hien, hoc thieu, hoc thiet
tran xuan » tran quang
tran van » luan van
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
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 thien hach - thanh ((tran xuan) or (tran van)) hung ((cong dan) OR (cong san)) than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thien hach - thanh ((tran xuan) OR (tran van)) hung ((cong dan) OR (cong san)) than cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - thanh ((tran xuan) or (tran van)) hung ((cong dan) OR (cong san)) than cau*".