Perhaps you should try some spelling variations:
dong hoa » dong hoc, dong co
ban hanh » ban hang
hien tu » khien tu, dien tu
hanh va » hang va, hanh vi
soc ban » hoc ban, coc ban, so ban
hieu tu » chieu tu, hieu tuc, lieu tu
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
sai ky » sac ky
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach ky) OR (sai ky)) dong hoa hoc. ((hieu tu) OR (hien tu)) cham soc ban hanh va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ky) OR (sai ky)) dong hoa hoc. ((hieu tu) OR (hien tu)) cham soc ban hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: so ((sach ky) OR (sai ky)) dong hoa hoc. ((hieu tu) OR (hien tu)) cham soc ban hanh va cua tre*.