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