Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh de » hanh ve, hanh kem
danh di » danh du, xanh di, danh dien
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cua tre » cua te, cuu tre, cua triet
va am » va lam, va cam
thuc » thu

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 ((ty nang) OR (ty hang)) xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (ty hang)) xa hoi. hieu va am thuc vat ((danh di) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) OR (ty hang)) xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty nang) OR (ty hang)) xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) cua tre*.