Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
hang den » hang dien, hang ben, huong den
su triet » su viet, su tien, ve triet
co sach » bo sach, cuon sach, hoc sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
va hang » van hang, va nang, va lang
thu va » thuc va, thue va, tu va
den su » dan su, nen su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: co sach thi nang xa hoi. ((hieu ve) or (hieu qua)) cam thu va hang den su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach thi nang xa hoi. ((hieu ve) OR (hieu qua)) cam thu va hang den su triet.
• Adding a wildcard symbol may retrieve word variants: co sach thi nang xa hoi. ((hieu ve) or (hieu qua)) cam thu va hang den su triet*.