Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ve triet » va trien, su triet
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
va dinh » van dinh, va kinh, va tinh
van am » van nam, van lam, van dam
va dan » ca dan, va dao, va dau
mai ve » mai va, moi ve, dai ve
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: toc sach ty nang x hoi. hieu van am thuc ((va dan) or (va dinh)) mai ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang x hoi. hieu van am thuc ((va dan) OR (va dinh)) mai ve triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang x hoi. hieu van am thuc ((va dan) or (va dinh)) mai ve triet*.