Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
su triet » su viet, su tien
ve triet » va trien
van hoi » van hoa, van hoc, van hoe
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
_ dang » _ dan, 2 dang, _ danh
y dang » ky dang, 2 dang, b dang
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((y dang) or (_ dang)) van hoi. hieu ve cac duc va danh vi ((su triet) OR (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((y dang) OR (_ dang)) van hoi. hieu ve cac duc va danh vi ((su triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((y dang) or (_ dang)) van hoi. hieu ve cac duc va danh vi ((su triet) OR (ve triet))".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((y dang) or (_ dang)) van hoi. hieu ve cac duc va danh vi ((su triet) OR (ve triet))*.