Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh lam » thanh lap, hanh kem, hanh va
dao truc » dao tuc, dao tru, dai truc
su viet » so viet
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
su tien » su kien, su hien, tu tieng
y nang » ky nang, ly nang, v 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 ma hoa. hieu va dao truc va hanh lam ((cua tre) or (((su viet) or (su tien))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoa. hieu va dao truc va hanh lam ((cua tre) OR (((su viet) OR (su tien)))).
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoa. hieu va dao truc va hanh lam ((cua tre) or (((su viet) or (su tien))))*.