Perhaps you should try some spelling variations:
"so danh thanh san thuat xay hoc" » "so dinh thanh san thuat xay hoc", "so dang thanh san thuat xay hoc", "so nhanh thanh san thuat xay hoc", "so danh thanh san xuat xay hoc", "so danh thanh va thuat xay hoc", "so danh thanh van thuan xay hoc", "do danh thanh san thuat xay hoc", "so sanh thanh san thuat xay hoc", "so dan thanh san thuat xay hoc", "so danh thanh san thuat day hoc", "so danh thanh san thuat xa hoc"
"so sach than ky thuat toan khoa" » "so sach tham ky thuat toan khoa", "so sach han ky thuat toan khoa", "so sach tranh ky thuat toan khoa", "so sanh than ky thuat toan khoa", "bo sach than ky thuat toan khoa", "co sach than ky thuat toan khoa", "so sach than ky thuat tran khoa"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("so danh thanh san thuat xay hoc") or ("so sach than ky thuat toan khoa"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so danh thanh san thuat xay hoc") OR ("so sach than ky thuat toan khoa")).
• Removing quotes may allow a broader search: (( so danh thanh san thuat xay hoc ) or ( so sach than ky thuat toan khoa )).
• Adding a wildcard symbol may retrieve word variants: (("so danh thanh san thuat xay hoc") or ("so sach than ky thuat toan khoa"))*.