Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va pham » van pham, va phat, va phan
lai cua » dai cua, hai cua, lai chau
dan lai » dan loai, dan lap, dan lat
va phap » va phat, ban phap
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
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 pham) OR (va phap)) duc va dan lai cua 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 pham) OR (va phap)) duc va dan lai cua 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 pham) OR (va phap)) duc va dan lai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty nang x hoi. hieu ((va pham) OR (va phap)) duc va dan lai cua tre*.