Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
van cac » van hac, van cau, dan cac
hanh di » hanh vi, hanh de, hang di
luc van » luoc van, luu van, duc van
van bac » van ban, van bao, van hac
te sach » toc sach
cho hoc » co hoc, khoa hoc
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cua cau » cua cac, cua chu, cua cay
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: te sach ((ty nang) or (ty hang)) cho hoc. hieu ((van cac) OR (van bac)) luc van hanh di cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty nang) OR (ty hang)) cho hoc. hieu ((van cac) OR (van bac)) luc van hanh di cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty nang) or (ty hang)) cho hoc. hieu ((van cac) OR (van bac)) luc van hanh di cua cau*".