Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
ky dang » ky nang
ky danh » ky anh
hieu va » lieu va, hieu qua
va cham » va chat, va tham
va hanh » va thanh, va danh, ban hanh
cu tren » tu tren, dua tren
vi cu » vi su, vi xu, vi du

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 dang) or (ky danh)) xa hoi. hieu va cham soc ((va hanh) OR (van hanh)) vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky dang) OR (ky danh)) xa hoi. hieu va cham soc ((va hanh) OR (van hanh)) vi cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky dang) or (ky danh)) xa hoi. hieu va cham soc ((va hanh) OR (van hanh)) vi cu tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky dang) or (ky danh)) xa hoi. hieu va cham soc ((va hanh) OR (van hanh)) vi cu tren*.