Perhaps you should try some spelling variations:
thiet tach » thien hach, thuat tach
chiet tach » chieu sach
nhanh hanh » nhanh thanh, nhanh thang, thanh thanh
thong cong » trong cong, tong cong, thong thong
va thong » va thuong, va phuong, he thong
dan than » dan chan, ban than, van than
van tuan » van quan, van ban, anh tuan
hanh va » hang va, hanh vi

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