Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
thu nong » thu cong, tu nong, phu nong
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
loai va » loai nam
va hanh » va thanh, va danh, ban hanh
tu sach » thu sach, su sach, te sach
nong xa » song xa, dong xa, nong va
va cam » va cham, va cac, va cao
ve cai » va cai, ve cac, ve tai

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 thu nong xa hoi. hieu ((ve cai) or (va cam)) duc ((va hanh) OR (van hanh)) loai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nong xa hoi. hieu ((ve cai) OR (va cam)) duc ((va hanh) OR (van hanh)) loai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nong xa hoi. hieu ((ve cai) or (va cam)) duc ((va hanh) OR (van hanh)) loai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thu nong xa hoi. hieu ((ve cai) or (va cam)) duc ((va hanh) OR (van hanh)) loai va triet*.