Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
cham tuc » nham thuc, pham thuc, tham thuc
va cham » va chat, va tham
dinh vi » dinh ve, dinh viet, dinh tri
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa

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