Perhaps you should try some spelling variations:
sach cam » sach cap, sach tham, sach dao
van hanh » van thanh, ban hanh, van anh
mach cam » mach cao, manh cam, mac ca
hanh ki » hanh vi, hanh ky, hanh kien
xuc van » duc van, luc van, vuc van
nang ma » tang ma, sang ma, nang cao
su tien » su kien, su hien, tu tieng
va cam » va cham, va cao, va cai
ma hoi » mai hoi, xa hoi, ma hoa
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 cam) OR (mach cam)) nang ma hoi. hieu ((va cam) or (va cac)) xuc van hanh ki su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach cam) OR (mach cam)) nang ma hoi. hieu ((va cam) OR (va cac)) xuc van hanh ki su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach cam) OR (mach cam)) nang ma hoi. hieu ((va cam) or (va cac)) xuc van hanh ki su tien".
• Adding a wildcard symbol may retrieve word variants: tu ((sach cam) OR (mach cam)) nang ma hoi. hieu ((va cam) or (va cac)) xuc van hanh ki su tien*.