Perhaps you should try some spelling variations:
"su sach ngonh ky thuat co hoc" » "su sach ngon ky thuat co hoc", "su sach ngan ky thuat co hoc", "su sach nganh ky thuat co hoc", "su sach ngonh ky thuat do hoc", "su sach ngonh ky thuat o hoc", "vu sach ngonh ky thuat co hoc"
"so sach danh hay thuyet va hoc" » "so sach danh thay thuyet va hoc", "so sach danh ly thuyet va hoc", "so sach danh hoc thuyet va hoc", "so sach tranh hay thuyet va hoc", "so sach dao hay thuyet va hoc", "so sach dung hay thuyet va hoc", "so sach anh hay thuyet va hoc", "so sach danh hau thuyet va hoc", "so sach danh nhan thuyet va hoc", "so sanh danh hay thuyet va hoc", "bo sach danh hay thuyet va hoc", "co sach danh hay thuyet va hoc", "so sach danh hay thuyet van 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 ngonh ky thuat co hoc") or ("so sach danh hay thuyet va hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach ngonh ky thuat co hoc") OR ("so sach danh hay thuyet va hoc"))*.
• Removing quotes may allow a broader search: (( su sach ngonh ky thuat co hoc ) or ( so sach danh hay thuyet va hoc ))*.