Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cam thuc » am thuc, nam thuc, cam thu
vat lanh » dat lanh, hat lanh, va lanh
va triet » va thiet, va trien, cua triet
ve triet » va trien, su triet
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hai. ((hieu va) OR (lieu va)) cam thuc vat lanh dao ((va triet) OR (ve triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hai. ((hieu va) or (lieu va)) cam thuc vat lanh dao ((va triet) OR (ve triet))~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hai. ((hieu va) or (lieu va)) cam thuc vat lanh dao ((va triet) OR (ve triet))*.