Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach
thuat tach » thuat sach, thuat mach, thuat tac
hanh tram » hanh tam, hanh trang, thanh tran
dung cong » dung trong
tram van » tran van, tam van, trang van
van dung » van dong, xay dung, tin dung
tan toan » tan tran, tap toan, dan toan
van toan » van tuan, van tan, van thanh

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) or (thuat tach)) - hanh tram van dung cong ((tan toan) OR (van toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (thuat tach)) - hanh tram van dung cong ((tan toan) OR (van toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) or (thuat tach)) - hanh tram van dung cong ((tan toan) OR (van toan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) or (thuat tach)) - hanh tram van dung cong ((tan toan) OR (van toan)) cau*.