Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
su triet » su viet, su tien, ve triet
chon loc » cho hoc
cua viet » ca viet, hoa viet, cua vat
tang van » dang van, hoang van, trong van
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
danh tu » anh tu, doanh thu
tang ma » mang may
ve chon » ve chong, ve cho, ve chuong
loc va » hoc 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: toc sach y ((tang ma) OR (tang van)) hoi. hieu ve chon loc va danh tu ((su triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((tang ma) OR (tang van)) hoi. hieu ve chon loc va danh tu ((su triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((tang ma) OR (tang van)) hoi. hieu ve chon loc va danh tu ((su triet) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((tang ma) OR (tang van)) hoi. hieu ve chon loc va danh tu ((su triet) or (cua viet))*.