Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
doc sach » hoc sach, toc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
su triet » su tien, ve triet
va hanh » va thanh, va danh, ban hanh
sach ky » sac ky, sach y, sach ty
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
su viet » so viet

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

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