Perhaps you should try some spelling variations:
tang thanh » dang thanh, trung thanh, hoang thanh
hieu van » hieu va, thien van, lieu va
duc tang » duc thang, duc tan, tuc tang
tu sach » thu sach, su sach, te sach
ly nang » ky nang, ly hang, ly vang
van bao » van ban, van dao
bao duc » dao duc, bao luc, cao duc
vai cua » hai cua, lai cua, bai cua
y nang » ky nang, v nang, may 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) OR (ly nang)) xa hoi. hieu van bao duc tang thanh ((vai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ly nang)) xa hoi. hieu van bao duc tang thanh ((vai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ly nang)) xa hoi. hieu van bao duc tang thanh ((vai cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ly nang)) xa hoi. hieu van bao duc tang thanh ((vai cua) or (dai cua)) tre*.