Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
danh di » danh du, xanh di, danh dien
va danh » va dinh, va dan, va hanh
lam loc » lam duoc, lam ngoc
cu tren » tu tren, dua tren
hieu va » lieu va
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
loc va » hoc va, luc va
di cu » di cau, di cua, di 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 ((y nang) or (v nang)) xa hoi. ((hieu va) OR (hieu qua)) lam loc va danh di cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) xa hoi. ((hieu va) OR (hieu qua)) lam loc va danh di cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) or (v nang)) xa hoi. ((hieu va) OR (hieu qua)) lam loc va danh di cu tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) or (v nang)) xa hoi. ((hieu va) OR (hieu qua)) lam loc va danh di cu tren*.