Perhaps you should try some spelling variations:
"so sach nganh ky thuat toan khoa" » "so sach ngan ky thuat toan khoa", "so cac nganh ky thuat toan khoa", "so sach danh ky thuat toan khoa", "so sach nganh y thuat toan khoa", "so sach nganh xay thuat toan khoa", "so sach hanh ky thuat toan khoa", "so sanh nganh ky thuat toan khoa", "bo sach nganh ky thuat toan khoa", "co sach nganh ky thuat toan khoa", "so sach nganh ky thuat tran khoa"
"so sach tranh ky thuat toan khoa" » "so canh tranh ky thuat toan khoa", "so sach trinh ky thuat toan khoa", "so sach thanh ky thuat toan khoa", "so sach hanh ky thuat toan khoa", "so sanh tranh ky thuat toan khoa", "bo sach tranh ky thuat toan khoa", "co sach tranh ky thuat toan khoa", "so sach tranh ky thuat tran khoa"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("so sach nganh ky thuat toan khoa") OR ("so sach tranh ky thuat toan khoa"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"so sach nganh ky thuat toan khoa\") OR (\"so sach tranh ky thuat toan khoa\"))".
• Removing quotes may allow a broader search: (( so sach nganh ky thuat toan khoa ) OR ( so sach tranh ky thuat toan khoa )).
• Adding a wildcard symbol may retrieve word variants: (("so sach nganh ky thuat toan khoa") OR ("so sach tranh ky thuat toan khoa"))*.