Perhaps you should try some spelling variations:
luat ngan » cua ngan, luat dan
cau tren » cu tren, dau tren, ca tren
hang vit » hang viet, hang vi, hang vat
luc ngan » luc nganh, luc nhan, vu ngan
vit cau » viet cau, vit ca
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu va » hieu qua
ty nang » ky nang, ty xang, ty hang
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 x hoi. ((hieu va) OR (lieu va)) cau ((luc ngan) or (luat ngan)) hang vit cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. ((hieu va) OR (lieu va)) cau ((luc ngan) OR (luat ngan)) hang vit cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. ((hieu va) OR (lieu va)) cau ((luc ngan) or (luat ngan)) hang vit cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. ((hieu va) OR (lieu va)) cau ((luc ngan) or (luat ngan)) hang vit cau tren*.