Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
van hanh » ban hanh, van anh, van ban
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
dau duc » dao duc, dang duc, dau nuoc
y nang » ky nang, ly nang, v nang
va dau » va dao
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 dau duc ((van hanh) OR (van thanh)) ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu va dau duc ((van hanh) OR (van thanh)) ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu va dau duc ((van hanh) OR (van thanh)) ((vi cua) or (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu va dau duc ((van hanh) OR (van thanh)) ((vi cua) or (di cua)) tre*.