Perhaps you should try some spelling variations:
thuong cong » thong cong, thuong con, thuong dong
canh trang » canh tranh, hanh trang, banh trang
hoc thiet » hoc thieu, hoc thuyet, hoc hien
thiet hai » thiet bi, thi hai, thien tai
van thanh » ban thanh, van tuan
trang va » tran van, hang va
van toan » van tuan, van tan, manh toan

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 hai - canh trang va thuong cong ((van toan) OR (van thanh)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet hai - canh trang va thuong cong ((van toan) OR (van thanh)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet hai - canh trang va thuong cong ((van toan) OR (van thanh)) cau*.