Perhaps you should try some spelling variations:
luc nhan » cu nhan, tue nhan, luc luan
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
ty nang » ty xang, ty hang, ly nang
hieu va » lieu va, hieu qua
hang ve » hang va, hanh ve, hang ke
va dau » va dao
ve cau » ke cau, va cau, ve cac
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: tu sach ((ty nang) OR (ky nang)) x hoi. hieu va dau ((luc nhan) or (luc nhat)) hang ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ky nang)) x hoi. hieu va dau ((luc nhan) OR (luc nhat)) hang ve cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ky nang)) x hoi. hieu va dau ((luc nhan) or (luc nhat)) hang ve cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ky nang)) x hoi. hieu va dau ((luc nhan) or (luc nhat)) hang ve cau tren*.