Perhaps you should try some spelling variations:
thiet tach » thien hach, thuat tach
chiet tach » chieu sach
truong cua » truong ca, truong quan, truong cao
nhung cong » dung cong, thong cong, hang cong
cong ngang » cong nhan, cong quang, cong lang
ngang toan » nganh toan, dang toan, quang toan
thang cua » thong cua, hang cua, than cua
toan ban » van ban

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)) - hanh ((thang cua) or (truong cua)) nhung cong ngang toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (chiet tach)) - hanh ((thang cua) OR (truong cua)) nhung cong ngang toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) OR (chiet tach)) - hanh ((thang cua) or (truong cua)) nhung cong ngang toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) OR (chiet tach)) - hanh ((thang cua) or (truong cua)) nhung cong ngang toan ban*.