Perhaps you should try some spelling variations:
sach thi » sach tai, sach thieu, sach tham
sach thu » sach thue, sach thieu, sach tham
hang xa » hoang xa, hang va, hang ca
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
dao su » dao suu, dan su, da su
va am » va lam, va cam

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach thi) OR (sach thu)) hang xa hoi. hieu va am thuc va hanh ((dao su) or (cao su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thi) OR (sach thu)) hang xa hoi. hieu va am thuc va hanh ((dao su) OR (cao su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach thi) OR (sach thu)) hang xa hoi. hieu va am thuc va hanh ((dao su) or (cao su)) triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach thi) OR (sach thu)) hang xa hoi. hieu va am thuc va hanh ((dao su) or (cao su)) triet*.