Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
va hanh » van hanh, va thanh, va danh
vu cham » va cham, vu kham, tu cham
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ve cham » va cham, ve chat, ve chim
luc va » duc va, tuc va, loc va
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: tu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cham) OR (vu cham)) luc va hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (nang x)) hoi. hieu ((ve cham) OR (vu cham)) luc va hanh vi su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cham) OR (vu cham)) luc va hanh vi su triet*".