Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
va cam » va cham, va cac, va cai
va cao » va cac, va co, va dao
thiet » thieu

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 ky nang ma hoa. hieu ((va cam) OR (va cao)) xuc ((va hanh) or (van thanh)) tri va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoa. hieu ((va cam) OR (va cao)) xuc ((va hanh) OR (van thanh)) tri va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoa. hieu ((va cam) OR (va cao)) xuc ((va hanh) or (van thanh)) tri va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoa. hieu ((va cam) OR (va cao)) xuc ((va hanh) or (van thanh)) tri va thiet*.