Perhaps you should try some spelling variations:
hoc thiet » hoc thieu, hoc thuyet, hoc hien
thiet anh » thien anh, thuyet anh, thien danh
cong manh » duong manh, cong thanh, hoang manh
cong danh » cuong danh, cong dan, cong thanh
trinh ke » trinh ky, trinh he, trinh tu
trinh do » trinh ky
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 thiet anh - canh ((trinh ke) or (trinh do)) huong ((cong manh) OR (cong danh)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet anh - canh ((trinh ke) OR (trinh do)) huong ((cong manh) OR (cong danh)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet anh - canh ((trinh ke) or (trinh do)) huong ((cong manh) OR (cong danh)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet anh - canh ((trinh ke) or (trinh do)) huong ((cong manh) OR (cong danh)) toan cau*.