Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
ty nang » ky nang, ty xang, ty hang
hanh ca » hanh cac, hanh cat, hanh cua
duc ban » duc van, dua ban, duc man
sach ty » sach y, sach tu, sach thu
ca cua » co cua
cua te » cua tu
va cao » va cac, va co, va dao
ve cam » ve cham, ve cac, va cam
nang o » nang co, nang ho, nang ro
o hoc » co hoc, mo hoc, so hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty nang o hoc. hieu ((ve cam) or (va cao)) ((duc ban) OR (duc tan)) hanh ca cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang o hoc. hieu ((ve cam) OR (va cao)) ((duc ban) OR (duc tan)) hanh ca cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang o hoc. hieu ((ve cam) or (va cao)) ((duc ban) OR (duc tan)) hanh ca cua te".
• Adding a wildcard symbol may retrieve word variants: so sach ty nang o hoc. hieu ((ve cam) or (va cao)) ((duc ban) OR (duc tan)) hanh ca cua te*.