Perhaps you should try some spelling variations:
sach ngan » sach ngon, sach nha, sach han
tranh cac » trinh cac, thanh cac, tranh cai
cac thuat » hoc thuat, cac thu, cac chat
va thuat » ky thuat, ki thuat, va thuc
tu sach » thu sach, su sach, te sach
ngan va » ngan van, nhan va, ngay va
tu canh » thu canh, tu chanh, tu can
toan » tran

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 ngan va thuat toan khoa ) or ( tu canh tranh cac thuat ((van hoc) OR (van hoa)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach ngan va thuat toan khoa ) OR ( tu canh tranh cac thuat ((van hoc) OR (van hoa)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach ngan va thuat toan khoa ) or ( tu canh tranh cac thuat ((van hoc) OR (van hoa)) ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach ngan va thuat toan khoa ) or ( tu canh tranh cac thuat ((van hoc) OR (van hoa)) ))*.