Perhaps you should try some spelling variations:
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
dau nuoc » dat nuoc, dau ngoc, cap nuoc
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 xua » dau cua, dao xuan, dau luan
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 van nang xa hoi. hieu va ((dau nuoc) or (dau xua)) van hanh ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach van nang xa hoi. hieu va ((dau nuoc) OR (dau xua)) van hanh ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach van nang xa hoi. hieu va ((dau nuoc) or (dau xua)) van hanh ((vi cua) OR (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach van nang xa hoi. hieu va ((dau nuoc) or (dau xua)) van hanh ((vi cua) OR (di cua)) tre*.