Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach, vu sach
ty hang » ly hang, ty xang, thi hang
hieu ve » hieu va
hanh va » hang va, hanh vi
su tien » su kien, su hien, tu tieng
y hang » ly hang, yu hang, _ hang
thuc » thu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((y hang) OR (ty hang)) hoa hoc. ((hieu ve) or (hieu van)) am thuc vat hanh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y hang) OR (ty hang)) hoa hoc. ((hieu ve) OR (hieu van)) am thuc vat hanh va su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y hang) OR (ty hang)) hoa hoc. ((hieu ve) or (hieu van)) am thuc vat hanh va su tien".
• Adding a wildcard symbol may retrieve word variants: su sach ((y hang) OR (ty hang)) hoa hoc. ((hieu ve) or (hieu van)) am thuc vat hanh va su tien*.