Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cua cau » cua cac, cua chu, cua can
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
van cac » van hac, van cau, van bac
te sach » toc sach
cho hoc » co hoc, khoa hoc
ty hang » ly hang, ty xang, thi hang
ty tang » tay tang, ty xang, ky tang
cua cay » cua cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((ty tang) or (ty hang)) cho hoc. hieu van cac vuc van hanh vi ((cua cau) OR (cua cay))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty tang) OR (ty hang)) cho hoc. hieu van cac vuc van hanh vi ((cua cau) OR (cua cay))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty tang) or (ty hang)) cho hoc. hieu van cac vuc van hanh vi ((cua cau) OR (cua cay))*".