Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
van hoe » van hoa, van hoc, van hieu
ly hang » ly quang
ly lang » ly vang, le lang, ly lanh
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua

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 ((ly lang) OR (ly hang)) van hoe. hieu ve cac ((xuc va) or (thuc vat)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((ly lang) OR (ly hang)) van hoe. hieu ve cac ((xuc va) OR (thuc vat)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((ly lang) OR (ly hang)) van hoe. hieu ve cac ((xuc va) or (thuc vat)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ((ly lang) OR (ly hang)) van hoe. hieu ve cac ((xuc va) or (thuc vat)) hanh vi cua tre*.