Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van ban
va cham » va chat, va tham
van anh » van thanh, tuan anh, van minh
tu sach » thu sach, su sach, te sach
sach vu » sach va, sach tu, sach uu
mai hoi » mai khoi, dai hoi, lai hoi
vu nang » vuc nang, va nang, vu dang
va cam » va cac, va cao, va cai
ki su » ky 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 vu nang mai hoi. hieu ((va cam) or (va cham)) xuc ((van hanh) OR (van anh)) ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang mai hoi. hieu ((va cam) OR (va cham)) xuc ((van hanh) OR (van anh)) ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang mai hoi. hieu ((va cam) or (va cham)) xuc ((van hanh) OR (van anh)) ki su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang mai hoi. hieu ((va cam) or (va cham)) xuc ((van hanh) OR (van anh)) ki su triet*.