Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
cua thong » cua thuong, cua khong, cua tong
so thiet » soc thiet, hoa thiet, tao thiet
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap
anh ban » anh bang, anh bai, anh van
ban cua » ban quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc thiet) OR (so thiet)) tach - anh ban cua thong cong dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thiet) OR (so thiet)) tach - anh ban cua thong cong dan toan cau*".