Perhaps you should try some spelling variations:
ban hanh » ban hang
sach ky » sach y, sach ty, sach kem
cuc ban » cua ban, cac ban, cuu ban
cam cuc » cam xuc, cham cuu, pham cuc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
lang ha » long ha
nang ma » tang ma, sang ma, nang cao
ve cam » ve cham, ve cac, va cam
sac ky » cac ky, sai ky
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) ((nang ma) OR (lang ha)) hoi. hieu ve cam cuc ban hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) ((nang ma) or (lang ha)) hoi. hieu ve cam cuc ban hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) ((nang ma) or (lang ha)) hoi. hieu ve cam cuc ban hanh vi cua tre*.