Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
thuc va » thuc dan, thuc day
hai cua » thai cua, dai cua, hoi cua
y tang » ky tang, 6 tang, 7 tang
ma hoi » mai hoi, ma hoa, me hoi
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y tang ((ma hoi) or (xa hoi)). hieu ve nam ((thuc va) OR (thuc vat)) hanh hai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y tang ((ma hoi) OR (xa hoi)). hieu ve nam ((thuc va) OR (thuc vat)) hanh hai cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y tang ((ma hoi) or (xa hoi)). hieu ve nam ((thuc va) OR (thuc vat)) hanh hai cua vat".
• Adding a wildcard symbol may retrieve word variants: so sach y tang ((ma hoi) or (xa hoi)). hieu ve nam ((thuc va) OR (thuc vat)) hanh hai cua vat*.