Perhaps you should try some spelling variations:
qua tham » qua cham, qua than, qua thanh
tham xuc » tham nuoc, tham thuc, pham duc
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
xuc van » duc van, luc van, vuc van
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
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 tu ((nang ma) OR (tang ma)) hoi. hieu qua tham xuc van hanh ki su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((nang ma) OR (tang ma)) hoi. hieu qua tham xuc van hanh ki su viet".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((nang ma) OR (tang ma)) hoi. hieu qua tham xuc van hanh ki su viet*.