Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
hoc sach » hoc sinh, hoc cac, hoc anh
dao duc » giao duc, tao duoc
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua su

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) OR (hoc sach)) ty nang xa hoi. hieu va ((cac duc) or (dao duc)) van hanh vi cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ty nang xa hoi. hieu va ((cac duc) OR (dao duc)) van hanh vi cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) ty nang xa hoi. hieu va ((cac duc) or (dao duc)) van hanh vi cua cu".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) ty nang xa hoi. hieu va ((cac duc) or (dao duc)) van hanh vi cua cu*.