Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nang doi » nang doc, hang doi, nang dong
nang noi » nang doc
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
van cau » van dau, van hau, van chat
cau tuc » cau truc, cau tu, cau luc

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 ky lang xa hoi. hieu van cau tuc xa ((nang doi) or (nang noi)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu van cau tuc xa ((nang doi) OR (nang noi)) va triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu van cau tuc xa ((nang doi) or (nang noi)) va triet*.