Perhaps you should try some spelling variations:
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
cao hoi » cau hoi, co hoi, cao hoc
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
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: thu ((sach ty) OR (sach tu)) nang cao hoi. hieu ((van cac) or (van hac)) dat va hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach tu)) nang cao hoi. hieu ((van cac) OR (van hac)) dat va hanh di cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) OR (sach tu)) nang cao hoi. hieu ((van cac) or (van hac)) dat va hanh di cua vat".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) OR (sach tu)) nang cao hoi. hieu ((van cac) or (van hac)) dat va hanh di cua vat*.