Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nhan duc » nhan duoc, nhan luc, than duc
phan duc » pham duc, phan tu, phan dau
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
va hanh » van hanh, va thanh, va danh
hoi cua » hoi chuc
y nang » ky nang, ly nang, v nang

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