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

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) OR (thu sach)) lo 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) OR (thu sach)) lo 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) OR (thu sach)) lo 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) OR (thu sach)) lo lang xa hoi. ((hieu van) or (hieu va)) cau duc va danh vai cua tre*.