Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
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
duc van » duc va, duc tan, duc manh
doi cua » dai cua, hoi cua, dong cua
y nang » ky nang, ly nang, v nang
va dau » va dao
vi cua » vai cua
di cua » dai cua, de cua, do 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 ((vi cua) or (((di cua) OR (doi 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 ((vi cua) OR (((di cua) OR (doi 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 ((vi cua) or (((di cua) OR (doi cua)))) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu va dau duc van hanh ((vi cua) or (((di cua) OR (doi cua)))) tre*.