Perhaps you should try some spelling variations:
luc nganh » luc ngan, chuc nganh, luat nganh
dua tren » dung tren
luc nhan » luc nhat, cu nhan, tue nhan
sach ty » sach y, sach tu, sach thu
la tren » loai tren, dat tren, dau tren
hang vi » hang va, hanh vi, hang di
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
xang xa » lang xa, mang xa, ang xa
ve cau » ke cau, va cau, ve cac

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