Perhaps you should try some spelling variations:
dat tren » dat trong, dua tren
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hang di » hang doi, hang vi, hang dien
cau luc » cau truc, cau phuc
tu sach » thu sach, su sach, te sach
cam luc » cam xuc
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma

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