Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cao phoi » cap phoi, cay phoi, cao phong
hanh di » hanh vi, hanh de, hang di
truc va » thuc va, trung va
di cua » dai cua, doi cua, de cua
ve cac » va cac, vien cac
ve cam » ve cham, va cam, ve cai
va cao » va cac, va co, va dao
y va » ly va, my va, ky va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y va cao phoi. hieu ((ve cam) OR (ve cac)) ((truc va) OR (thuc vat)) hanh di cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y va cao phoi. hieu ((ve cam) OR (ve cac)) ((truc va) or (thuc vat)) hanh di cua vat~".
• Adding a wildcard symbol may retrieve word variants: doc sach y va cao phoi. hieu ((ve cam) OR (ve cac)) ((truc va) or (thuc vat)) hanh di cua vat*.