Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
cam truc » nam truc, lam truoc, nam truoc
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
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: su sach ky nang xa hoi. hieu va ((cam truc) OR (cau truc)) va ((hang di) or (hang vi)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu va ((cam truc) OR (cau truc)) va ((hang di) OR (hang vi)) va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. hieu va ((cam truc) OR (cau truc)) va ((hang di) or (hang vi)) va triet*".