Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
luoc van » luoc can, luoc va, luot van
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
luc van » luu van, duc van, luc va
x hoi » xa hoi, o hoi, x ho
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 ky nang x hoi. ((hieu va) or (lieu va)) cham ((luc van) OR (luoc van)) hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang x hoi. ((hieu va) OR (lieu va)) cham ((luc van) OR (luoc van)) hanh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang x hoi. ((hieu va) or (lieu va)) cham ((luc van) OR (luoc van)) hanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang x hoi. ((hieu va) or (lieu va)) cham ((luc van) OR (luoc van)) hanh vi su triet*.