Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
van cam » van nam, van lam, van cau
duc van » duc va, duc manh, duc phan
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
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: tu ((sach ty) OR (sach tu)) nang x hoi. hieu van cam ((duc van) or (duc tan)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach tu)) nang x hoi. hieu van cam ((duc van) OR (duc tan)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) OR (sach tu)) nang x hoi. hieu van cam ((duc van) or (duc tan)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) OR (sach tu)) nang x hoi. hieu van cam ((duc van) or (duc tan)) hanh vi cua tre*.