Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va trien » va truyen, va thiet, va tuyen
thanh va » thanh van, hanh va, thanh ha
cao duc » dao duc, cao suc, giao duc
tu sach » thu sach, su sach, te sach
cao hoc » co hoc, cho hoc, chat hoc
cam duc » cam xuc, pham duc, nam duoc
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 ((cam duc) OR (cao 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 ((cam duc) OR (cao duc)) ban thanh va va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) or (v nang)) cao hoc. hieu qua ((cam duc) OR (cao 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 ((cam duc) OR (cao duc)) ban thanh va va trien*.