Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
va danh » va dinh, va dan, va hanh
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 ly nang xa hoi. ((hieu van) or (hieu va)) cau duc va danh ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly nang xa hoi. ((hieu van) OR (hieu va)) cau duc va danh ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly nang xa hoi. ((hieu van) or (hieu va)) cau duc va danh ((vi cua) OR (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ly nang xa hoi. ((hieu van) or (hieu va)) cau duc va danh ((vi cua) OR (di cua)) tre*.