Perhaps you should try some spelling variations:
"su sach ngon ky thuat co hoc" » "su sach ngan ky thuat co hoc", "su canh ngon ky thuat co hoc", "su gach ngoi ky thuat co hoc", "su sach ngon ky thuat do hoc", "su sach ngon ky thuat o hoc", "so sach ngon ky thuat co hoc", "vu sach ngon ky thuat co hoc", "su sach ngon keo thuat co hoc"
"so danh ngon hay thuat toan hoc" » "so danh nhan hay thuat toan hoc", "so dinh ngoc hay thuat toan hoc", "so danh ngon phau thuat toan hoc", "so danh ngon my thuat toan hoc", "so danh ngon va thuat toan hoc", "so danh ngan hay thuat toan hoc", "so danh ngoc hai thuat toan hoc", "so danh ngoc ha thuat toan hoc", "so danh ngon hay thuat toan khoa", "so danh ngon hay thuat van hoc", "so danh ngon hay thuat hoa hoc", "do danh ngon hay thuat toan hoc", "so sanh ngon hay thuat toan hoc", "so dan ngon hay thuat toan hoc"

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 ngon ky thuat co hoc") or ("so danh ngon hay thuat toan hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach ngon ky thuat co hoc") OR ("so danh ngon hay thuat toan hoc")).
• Removing quotes may allow a broader search: (( su sach ngon ky thuat co hoc ) or ( so danh ngon hay thuat toan hoc )).
• Adding a wildcard symbol may retrieve word variants: (("su sach ngon ky thuat co hoc") or ("so danh ngon hay thuat toan hoc"))*.