Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
thanh vai » thanh hai, thanh van, thanh tai
nam thuc » nam thuoc, am thuc, nam thu
thuc day » thuc dan, thuc vat
va triet » va trien, ve triet, cua triet
su sach » so sach, vu sach
ly nang » ly hang, ly vang, ly quang
hieu ve » hieu va, hieu van
ve nam » he nam, va nam, le nam
thiet » thieu

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

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