Perhaps you should try some spelling variations:
thiet danh » thien danh, thien anh, thien dang
canh trinh » canh tranh, hanh trinh, canh tinh
thong cong » tong cong, thong thong, phong chong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trinh va » trinh van, trinh vat, trinh ve
than cau » toan cau, phan cau, thanh chau
than cap » khan cap, thanh lap, thanh cac

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 danh - canh trinh va ((thong cong) OR (trong cong)) dan ((than cau) OR (than cap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet danh - canh trinh va ((thong cong) OR (trong cong)) dan ((than cau) OR (than cap))".
• Adding a wildcard symbol may retrieve word variants: hoc thiet danh - canh trinh va ((thong cong) OR (trong cong)) dan ((than cau) OR (than cap))*.