Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
sach ky » sac ky, sach y, sach ty
cao hoc » co hoc, cho hoc, chat hoc
hieu ve » hieu va
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang cao hoc. ((hieu ve) OR (hieu van)) cam xuc va ((hanh di) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang cao hoc. ((hieu ve) OR (hieu van)) cam xuc va ((hanh di) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang cao hoc. ((hieu ve) OR (hieu van)) cam xuc va ((hanh di) or (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang cao hoc. ((hieu ve) OR (hieu van)) cam xuc va ((hanh di) or (hanh de)) cua tre*.