Perhaps you should try some spelling variations:
va danh » va dinh, va dan, va hanh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
vi cau » ve cau, di cau, viet cau
va cau » van cau, va cac, va dau
va cam » va cham, va cac, va cao
x hoi » xa hoi, o hoi, x ho

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