Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cao hoi » cau hoi, co hoi, cao hoc
van cac » van hac, van cau, van bac
dac va » day va, dat va, dai va
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang cao hoi. hieu van cac ((dac va) OR (duc va)) hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang cao hoi. hieu van cac ((dac va) OR (duc va)) hanh vi cua viet*.