Perhaps you should try some spelling variations:
"te sach ngan hay thuat co hoc" » "te sach ngon hay thuat co hoc", "te sach nha hay thuat co hoc", "te sach han hay thuat co hoc", "te sach ngan phau thuat co hoc", "te sach ngan ky thuat co hoc", "te sach ngan my thuat co hoc", "te sach ngan han thuat co hoc", "te sach ngan hang thuat co hoc", "te sach nganh xay thuat co hoc", "te sach ngan hay thuat do hoc", "te sach ngan hay thuat o hoc", "toc sach ngan hay thuat co hoc"
"tu can trinh kxy thuat ban hoc" » "tu can tranh kxy thuat ban hoc", "tu dan trinh kxy thuat ban hoc", "tu van trinh kxy thuat ban hoc", "tu can trinh ky thuat ban hoc", "tu can trinh ly thuat ban hoc", "tu can trinh ke thuat ban hoc", "tu can trinh ki thuat ban hoc", "tu can trinh my thuat ban hoc", "tu can trinh kxy thuat bai hoc", "tu can trinh kxy thuat bao hoc", "tu can trinh kxy thuat san hoc", "tu can trinh kxy thuat bang hoc", "tu can trinh kxy thuat van hoc", "tu ban trinh kxy thuat ban hoc", "tu cac trinh kxy thuat ban hoc", "thu canh trinh kxy thuat ban hoc"

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: (("te sach ngan hay thuat co hoc") or ("tu can trinh kxy thuat ban hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach ngan hay thuat co hoc") OR ("tu can trinh kxy thuat ban hoc")).
• Removing quotes may allow a broader search: (( te sach ngan hay thuat co hoc ) or ( tu can trinh kxy thuat ban hoc )).
• Adding a wildcard symbol may retrieve word variants: (("te sach ngan hay thuat co hoc") or ("tu can trinh kxy thuat ban hoc"))*.