Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
hoc thiet » hoc thieu, hoc thuyet, hoc hien
hanh tran » hanh trang, thanh tran, hanh tram
van dung » xay dung, tin dung
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
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 tach - hanh tran ((van dung) OR (van dong)) cong dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - hanh tran ((van dung) OR (van dong)) cong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - hanh tran ((van dung) OR (van dong)) cong dan toan cau*.