Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
cao duc » cao suc, giao duc, tao duoc
vai cuu » vai cua
xa hanh » xa thanh, xa khanh, va hanh
dao duc » giao duc, tao duoc
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
nong xa » song xa, dong xa, nong va
tu nong » tu dong, tu cong, tu tong

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)) tu nong xa hoi. hieu va ((cao duc) or (dao duc)) xa hanh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tu nong xa hoi. hieu va ((cao duc) OR (dao duc)) xa hanh vai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) tu nong xa hoi. hieu va ((cao duc) or (dao duc)) xa hanh vai cuu tre*.