Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dao truc » dao tuc, dao tru, dai truc
hanh lam » thanh lap, hanh kem, hanh va
su triet » su viet, su tien, ve triet
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
va dao » ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((y nang) OR (ky nang)) ma hoa. hieu va dao truc va hanh lam ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y nang) OR (ky nang)) ma hoa. hieu va dao truc va hanh lam ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((y nang) OR (ky nang)) ma hoa. hieu va dao truc va hanh lam ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: toc sach ((y nang) OR (ky nang)) ma hoa. hieu va dao truc va hanh lam ((cua tre) or (su triet))*.