Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ty » sach y, sach tu, sach thu
hieu va » hieu qua
cac loc » cac lop, cac toc, cac hoc
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dau, va dap
va dao » ca dao
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty nang xa hoi. ((hieu va) or (lieu va)) cac loc ((va dan) OR (va dao)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang xa hoi. ((hieu va) OR (lieu va)) cac loc ((va dan) OR (va dao)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang xa hoi. ((hieu va) or (lieu va)) cac loc ((va dan) OR (va dao)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang xa hoi. ((hieu va) or (lieu va)) cac loc ((va dan) OR (va dao)) vi cua tre*.