Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
va triet » va thiet, va trien, ve triet
truc ban » thuc ban, truc van, truoc bang
truc dan » thuc dan, tuc dan, truc dai
hieu va » lieu va, hieu qua
ky danh » ky anh
ky dang » ky nang
tu sach » thu sach, su sach, te sach
hai va » hai van, thai va, hoi 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)) xa hoi. hieu va cac ((truc ban) OR (truc dan)) thanh hai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky dang) OR (ky danh)) xa hoi. hieu va cac ((truc ban) OR (truc dan)) thanh hai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky dang) or (ky danh)) xa hoi. hieu va cac ((truc ban) OR (truc dan)) thanh hai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky dang) or (ky danh)) xa hoi. hieu va cac ((truc ban) OR (truc dan)) thanh hai va triet*.