Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
luc ngan » luc nganh, luc nhan, luat ngan
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
tu sach » su sach, te sach, tu cach
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
cau luc » cau truc, cau phuc
hang vi » hang va, hanh vi, hang di
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) or (thu sach)) ty xang xa hoi. hieu ve cau luc ngan hang vi ((cau tren) OR (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty xang xa hoi. hieu ve cau luc ngan hang vi ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty xang xa hoi. hieu ve cau luc ngan hang vi ((cau tren) OR (dau tren))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty xang xa hoi. hieu ve cau luc ngan hang vi ((cau tren) OR (dau tren))*.