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
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
hieu ve » hieu van
vi cau » va cau, ve cau, di cau

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