Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
va trien » va truyen, va thiet, va tuyen
tu sach » thu sach, su sach, te sach
cao hoc » co hoc, cho hoc, chat hoc
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
va va » va van, va vua, va vai

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 ((y nang) or (v nang)) cao hoc. hieu qua cac duc ban thanh va va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) cao hoc. hieu qua cac duc ban thanh va va trien.
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) or (v nang)) cao hoc. hieu qua cac duc ban thanh va va trien*.