Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
chieu sach » chinh sach, chiet tach, chieu sang
hanh hang » thanh hang, hang hang, hanh han
dung cong » dung trong
hang tai » hang va, dung tai
tai dung » trai dung, thi dung, mai dung
cong dan » cong san, cong tan, huong dan
than cau » phan cau, than cap, thanh chau
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 ((thien hach) or (chieu sach)) - hanh hang tai dung cong dan ((than cau) OR (toan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (chieu sach)) - hanh hang tai dung cong dan ((than cau) OR (toan cau))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien hach) or (chieu sach)) - hanh hang tai dung cong dan ((than cau) OR (toan cau))*".