Perhaps you should try some spelling variations:
luc ngan » luc nganh, luc nhan, luat ngan
tu sach » thu sach, su sach, te sach
hang vi » hanh vi, hang di, khang voi
cau luc » cau truc, cau phuc
hieu ve » hieu va, hieu van
ty nang » ky nang, ty hang, ly nang
ca tren » cau tren, cu tren, la tren
ve cau » ke cau, va cau, ve cac
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ty nang) or (ty xang)) o hoi. hieu ve cau luc ngan ((hang vi) OR (hang va)) ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty xang)) o hoi. hieu ve cau luc ngan ((hang vi) OR (hang va)) ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) or (ty xang)) o hoi. hieu ve cau luc ngan ((hang vi) OR (hang va)) ca tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) or (ty xang)) o hoi. hieu ve cau luc ngan ((hang vi) OR (hang va)) ca tren*.