Perhaps you should try some spelling variations:
sach kem » hanh kem
sach ky » sach y, sach ty, sach hay
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
ve bac » ve bao, ve cac, ve ban
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho
bo va » bao va, do va, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((((sach ky) OR (sach kem))) or (sac ky)) nang x hoi. hieu ve bac bo va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((((sach ky) OR (sach kem))) OR (sac ky)) nang x hoi. hieu ve bac bo va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((((sach ky) OR (sach kem))) or (sac ky)) nang x hoi. hieu ve bac bo va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((((sach ky) OR (sach kem))) or (sac ky)) nang x hoi. hieu ve bac bo va hanh vi cua tre*.