Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
luc ngan » luc nganh, luc nhan, luat ngan
hang vi » hang va, hanh vi, hang di
cau luc » cau truc, cau phuc
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
hieu va » lieu va
vi cau » va cau, ve cau, di cau
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) or (sach tu)) nang x hoi. ((hieu va) OR (hieu qua)) cau luc ngan hang vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach tu)) nang x hoi. ((hieu va) OR (hieu qua)) cau luc ngan hang vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach tu)) nang x hoi. ((hieu va) OR (hieu qua)) cau luc ngan hang vi cau tren".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach tu)) nang x hoi. ((hieu va) OR (hieu qua)) cau luc ngan hang vi cau tren*.