Perhaps you should try some spelling variations:
chat doc » chat hoc, chau doc, thuat doc
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, dia danh, va thanh
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
va viet » hoa viet, san viet, mai viet
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dau
dai va » mai va

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 xa hoi. hieu va chat doc ((((va danh) OR (va hanh))) or (va dan)) dai va viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu va chat doc ((((va danh) OR (va hanh))) OR (va dan)) dai va viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu va chat doc ((((va danh) OR (va hanh))) or (va dan)) dai va viet*".