Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
ban anh » ban hanh, ban banh, ban danh
xuc ban » duc ban, cuc ban, quoc ban
vi cua » vai cua, di cua
anh vi » hanh vi, anh va, anh ve
sac ky » cac ky, sai ky
ve cai » va cai, ve cac, ve tai
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 ((sac ky) or (sach ty)) nang x hoi. hieu ((ve cai) or (vien cac)) xuc ban anh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach ty)) nang x hoi. hieu ((ve cai) OR (vien cac)) xuc ban anh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach ty)) nang x hoi. hieu ((ve cai) or (vien cac)) xuc ban anh vi cua tre*.