Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh dai » hanh tai, hanh dao, vanh dai
dai cuu » dai cua, dai huu
va hanh » van hanh, va thanh, va danh
cac duc » cao duc, cac dac, cac nuoc
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
cuu tre » cua tre, cau tren, cau treo
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ty nang x hoi. hieu va ((cac duc) or (cac du)) va hanh dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty nang x hoi. hieu va ((cac duc) OR (cac du)) va hanh dai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ty nang x hoi. hieu va ((cac duc) or (cac du)) va hanh dai cuu tre*".