Perhaps you should try some spelling variations:
chiet tach » chieu sach
hoc chiet » hoc thiet, hoc nhiet, hoc hien
trinh vat » trinh van, trinh luat, sinh vat
hang cong » dang cong, hang nong, bang cong
van thanh » ban thanh, van tuan
trinh ve » trinh he, trinh va, trinh vi
van phan » van phong, luan phan, 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 chiet tach - hanh ((trinh vat) or (trinh ve)) hang cong ((van phan) OR (van thanh)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc chiet tach - hanh ((trinh vat) OR (trinh ve)) hang cong ((van phan) OR (van thanh)) tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc chiet tach - hanh ((trinh vat) or (trinh ve)) hang cong ((van phan) OR (van thanh)) tap".
• Adding a wildcard symbol may retrieve word variants: hoc chiet tach - hanh ((trinh vat) or (trinh ve)) hang cong ((van phan) OR (van thanh)) tap*.