Perhaps you should try some spelling variations:
sach ky » sach y, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
ve cham » va cham, ve chat, vu cham
vu kham » vu khanh
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
vi va » vi van, vai va, vu va
thiet » thieu

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) OR (sac ky)) nang cao hoi. hieu ((ve cham) or (vu kham)) xuc va hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang cao hoi. hieu ((ve cham) OR (vu kham)) xuc va hanh vi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang cao hoi. hieu ((ve cham) or (vu kham)) xuc va hanh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang cao hoi. hieu ((ve cham) or (vu kham)) xuc va hanh vi va thiet*.