Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
hanh di » hanh vi, hanh de, hang di
hieu ve » hieu va, hieu van
xay hoi » xa hoi, tay hoi, cay phoi
ly dong » ly dung, lao dong, huy dong
ly dang » ly hang, le dang, ly dung
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ((ly dang) OR (ly dong)) xay hoi. hieu ve cam ((duc va) or (thuc vat)) hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((ly dang) OR (ly dong)) xay hoi. hieu ve cam ((duc va) OR (thuc vat)) hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((ly dang) OR (ly dong)) xay hoi. hieu ve cam ((duc va) or (thuc vat)) hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ((ly dang) OR (ly dong)) xay hoi. hieu ve cam ((duc va) or (thuc vat)) hanh di cua tre*.