Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
va hanh » va thanh, va danh, ban hanh
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
di cua » dai cua, doi cua, de cua
ke cau » ket cau
ve cau » va cau, ve cac, le cau
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 x hoi. hieu ((ve cau) or (ke cau)) luc ((va hanh) OR (van hanh)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang x hoi. hieu ((ve cau) OR (ke cau)) luc ((va hanh) OR (van hanh)) di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang x hoi. hieu ((ve cau) or (ke cau)) luc ((va hanh) OR (van hanh)) di cua te".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang x hoi. hieu ((ve cau) or (ke cau)) luc ((va hanh) OR (van hanh)) di cua te*.