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 han hay thuyet va hoc" » "so sach han thay thuyet va hoc", "so sach han ly thuyet va hoc", "so sach han hoc thuyet va hoc", "so sach tham hay thuyet va hoc", "so sach danh hay thuyet va hoc", "so sach nang hay thuyet va hoc", "so sanh han hay thuyet va hoc", "bo sach han hay thuyet va hoc", "co sach han hay thuyet va hoc", "so sach hang hay thuyet va hoc", "so sach han day thuyet va hoc", "so sach han tay thuyet va hoc", "so sach han 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 han 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 han hay thuyet va hoc"))*.
• Removing quotes may allow a broader search: (( su sach ngonh ky thuat co hoc ) or ( so sach han hay thuyet va hoc ))*.