Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
truc va » thuc va, thuc vat, trung va
hoi cua » hoi chuc
hai cua » thai cua, dai cua, lai cua
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
luc va » duc va, tuc va, loc va

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