Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cham luc » nhan luc, cham cuu, chat lua
ly quang » le quang, vu quang
quang xa » quan xa, quang ma, quang va
tu sach » su sach, te sach, tu cach
dao cua » dai cua, day cua, dan cua
hieu va » lieu va, hieu qua
cua cua » cua chua, ca cua, qua cua
va dao » ca dao

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)) ly quang xa hoi. hieu va ((cham luc) OR (cham soc)) va dao cua cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ly quang xa hoi. hieu va ((cham luc) OR (cham soc)) va dao cua cua vat*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ly quang xa hoi. hieu va ((cham luc) OR (cham soc)) va dao cua cua vat*".