Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
dan thanh » dang thanh, danh thanh, ban thanh
va triet » va thiet, va trien, ve triet
thuc dan » thuc hanh, hoc dan, thuc vat
va cham » va chat, va tham
tu sach » thu sach, su sach, te sach
ty dang » ky dang, ty hang, ty dong
ve chim » va chim, ve cham, ve chinh

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 ((ty dang) OR (ty xang)) xa hoi. hieu ((ve chim) or (va cham)) thuc dan thanh dat va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty dang) OR (ty xang)) xa hoi. hieu ((ve chim) OR (va cham)) thuc dan thanh dat va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty dang) OR (ty xang)) xa hoi. hieu ((ve chim) or (va cham)) thuc dan thanh dat va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty dang) OR (ty xang)) xa hoi. hieu ((ve chim) or (va cham)) thuc dan thanh dat va triet*.