Perhaps you should try some spelling variations:
"tu canh trinh ky thuat ban hoc" » "tu canh tranh ky thuat ban hoc", "tu hanh trinh ky thuat ban hoc", "tu canh tinh ky thuat ban hoc", "tu canh trinh ky thuat bai hoc", "tu canh trinh ky thuat bao hoc", "tu canh trinh ky thuat san hoc", "thu canh trinh ky thuat ban hoc", "tu chanh trinh ky thuat ban hoc", "tu can trinh ky thuat ban hoc", "tu canh trinh ky thuat bang hoc", "tu canh trinh ky thuat van hoc"
"te sach nha ky thuat do hoc" » "te sach nha ky thuat o hoc", "toc sach nha ky thuat do hoc", "te sach nhat ky thuat do hoc", "te sach nhan ky thuat do hoc", "te sach nha ly thuat do hoc", "te sach nha ky thuat co hoc", "te sach nha ky thuat do hoa", "te sach nha ky thuat du 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 nha ky thuat do hoc") or ("tu canh trinh ky thuat ban hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach nha ky thuat do hoc") OR ("tu canh trinh ky thuat ban hoc")).
• Removing quotes may allow a broader search: (( te sach nha ky thuat do hoc ) or ( tu canh trinh ky thuat ban hoc )).
• Adding a wildcard symbol may retrieve word variants: (("te sach nha ky thuat do hoc") or ("tu canh trinh ky thuat ban hoc"))*.