Perhaps you should try some spelling variations:
thuyet tach » thuyet mach, thuyet xac, thuyet cac
thuyet hach » thuyet mach, thuyet xac, thuyet cac
hanh trinh » canh tranh, hanh chinh
thong cong » trong cong, tong cong, thong thong
manh toan » thanh toan, anh tuan, tinh toan
trinh ve » trinh he, trinh va, trinh vi
ve thong » he thong, va thong, ve phong
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 ((thuyet tach) OR (thuyet hach)) - hanh trinh ve thong cong ((manh toan) or (van toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thuyet tach) OR (thuyet hach)) - hanh trinh ve thong cong ((manh toan) OR (van toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thuyet tach) OR (thuyet hach)) - hanh trinh ve thong cong ((manh toan) or (van toan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thuyet tach) OR (thuyet hach)) - hanh trinh ve thong cong ((manh toan) or (van toan)) cau*.