Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cham sac » pham sach, cap sac, cham mat
su sach » so sach, vu sach
hanh de » hanh ve, hanh kem
hieu vu » hieu va, hieu ve, hieu su
ty lang » tay lang, ty hang, tu lang
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua

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 ((ty lang) or (ty xang)) xa hoi. hieu vu ((cham sac) OR (cham soc)) van hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty lang) OR (ty xang)) xa hoi. hieu vu ((cham sac) OR (cham soc)) van hanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty lang) or (ty xang)) xa hoi. hieu vu ((cham sac) OR (cham soc)) van hanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty lang) or (ty xang)) xa hoi. hieu vu ((cham sac) OR (cham soc)) van hanh de cua tre*.