Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
chinh ca » chinh ta, chinh va, chinh tai
ky lang » ky dang, ky tang, tay lang
van cam » van nam, van lam, van cau
tuc va » thuc va, truc va, duc va
ca te » cua te, ca ve, ca me

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) or (ky nang)) xa hoi. hieu van cam ((tuc va) OR (tuc xa)) hanh chinh ca te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky nang)) xa hoi. hieu van cam ((tuc va) OR (tuc xa)) hanh chinh ca te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) or (ky nang)) xa hoi. hieu van cam ((tuc va) OR (tuc xa)) hanh chinh ca te".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky lang) or (ky nang)) xa hoi. hieu van cam ((tuc va) OR (tuc xa)) hanh chinh ca te*.