Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
khoa hoi » khoan hoi, khoa doi, khoa noi
khoa hoc » hoa hoc
te sach » toc sach
thuc va » thuc dan, thuc day
su viet » so viet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ky lang » ky nang, ky dang, ky tang
vai su » va su, van su, lai su
ve nam » he nam, va nam, le nam

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: te sach ky lang ((khoa hoi) OR (khoa hoc)). hieu ve nam ((thuc va) OR (thuc vat)) hanh vai su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang ((khoa hoi) OR (khoa hoc)). hieu ve nam ((thuc va) or (thuc vat)) hanh vai su viet~".
• Adding a wildcard symbol may retrieve word variants: te sach ky lang ((khoa hoi) OR (khoa hoc)). hieu ve nam ((thuc va) or (thuc vat)) hanh vai su viet*.