Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
vu khach » vu khanh, vu khac, vay khach
nam thuc » nam thuoc, am thuc, nam tu
su triet » su viet, su tien, ve triet
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (vu khach)) ky nang xa hoi. hieu ve ((nam thuc) OR (nam thu)) va hanh vi su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (vu khach)) ky nang xa hoi. hieu ve ((nam thuc) OR (nam thu)) va hanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (vu khach)) ky nang xa hoi. hieu ve ((nam thuc) OR (nam thu)) va hanh vi su triet*.