Perhaps you should try some spelling variations:
nhan luc » nang luc
tu sach » thu sach, su sach, te sach
hoi cua » hoi chuc
hai cua » thai cua, dai cua, lai cua
va hanh » van hanh, va thanh, va danh
va nhan » van nhan, ca nhan, va phan
hieu va » lieu va, hieu qua
ly hang » ly quang
ly nang » ky nang, ly vang, ly quang
ma hoi » mai hoi, xa hoi, ma hoa
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 ((ly nang) OR (ly hang)) ma hoi. hieu va nhan luc va hanh ((hai cua) or (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ly nang) OR (ly hang)) ma hoi. hieu va nhan luc va hanh ((hai cua) OR (hoi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ly nang) OR (ly hang)) ma hoi. hieu va nhan luc va hanh ((hai cua) or (hoi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ly nang) OR (ly hang)) ma hoi. hieu va nhan luc va hanh ((hai cua) or (hoi cua)) tre*.