Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
danh vai » danh sai, danh va, doanh van
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cau duc » cao duc, cau luc, chu duc
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
lo lang » so lang, le lang, hoa lang
cua tre » cua te, cuu tre, cua triet
o lang » hoa lang, hoi lang

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 ((lo lang) OR (o lang)) xa hoi. ((hieu van) or (hieu va)) cau duc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((lo lang) OR (o lang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((lo lang) OR (o lang)) xa hoi. ((hieu van) or (hieu va)) cau duc va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((lo lang) OR (o lang)) xa hoi. ((hieu van) or (hieu va)) cau duc va danh vai cua tre*.