Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
va hanh » va thanh, va danh, ban hanh
tu sach » thu sach, su sach, te sach
ky danh » ky anh
ky dang » ky nang
hieu ve » hieu va, hieu van
ha hoi » hoa hoi, ha noi, xa hoi
ve nam » he nam, va nam, le nam
vi va » vi van, vai va, vu va

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

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