Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ly nang
ty hang » ly hang, ty xang, thi hang
nam xua » nam cua, nam mua, nam qua
xua van » xua va, qua van, cua van
vai cua » hai cua, lai cua, bai 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 ((ty nang) OR (ty hang)) xa hoi. hieu van nam xua van hanh ((vai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) xa hoi. hieu van nam xua van hanh ((vai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ty hang)) xa hoi. hieu van nam xua van hanh ((vai cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ty hang)) xa hoi. hieu van nam xua van hanh ((vai cua) or (dai cua)) tre*.