Perhaps you should try some spelling variations:
cac truc » cau truc, cac tru, cac trung
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, tao hoi
cao hoc » co hoc, cho hoc, chat hoc
hieu ve » hieu va, hieu van
va hanh » va thanh, va danh, ban hanh
luu tre » luu tru, cuu tre, luy tre
ve cac » va cac, vien cac
vi luu » vi lua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ((cao hoi) or (cao hoc)). hieu ve cac truc ((va hanh) OR (van hanh)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((cao hoi) OR (cao hoc)). hieu ve cac truc ((va hanh) OR (van hanh)) vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((cao hoi) or (cao hoc)). hieu ve cac truc ((va hanh) OR (van hanh)) vi luu tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((cao hoi) or (cao hoc)). hieu ve cac truc ((va hanh) OR (van hanh)) vi luu tre*.