Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, tu cach
nang xa » nang x, lang xa, nang ma
qua cam » qua cham, qua cac, qua ca
cam vuc » cam xuc
vuc van » duc van, luc van, thuc van
tai su » tai so, tai tu, lai su

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 (((te sach) OR (toc sach)))) ky nang xa hoi. hieu qua cam vuc van hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (((te sach) OR (toc sach)))) ky nang xa hoi. hieu qua cam vuc van hanh tai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (((te sach) OR (toc sach)))) ky nang xa hoi. hieu qua cam vuc van hanh tai su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (((te sach) OR (toc sach)))) ky nang xa hoi. hieu qua cam vuc van hanh tai su triet*.