Perhaps you should try some spelling variations:
"so sach nganh ky thuat tran khoa" » "so sach ngan ky thuat tran khoa", "so cac nganh ky thuat tran khoa", "so sach danh ky thuat tran khoa", "so sach nganh ky thuat trang khoa", "so sach nganh ky thuat than khoa", "so sach nganh ky thuat tren khoa", "so sach nganh ky thuat san khoa", "so sach nganh ky thuat nhan khoa", "so sach nganh ky thuat van khoa", "so sach nganh y thuat tran khoa", "so sach nganh xay thuat tran khoa", "so sach hanh ky thuat tran khoa", "so sanh nganh ky thuat tran khoa", "bo sach nganh ky thuat tran khoa", "co sach nganh ky thuat tran khoa"
"so sach tranh ky thuat toan khoa" » "so canh tranh ky thuat toan khoa", "so sach trinh ky thuat toan khoa", "so sach thanh ky thuat toan khoa", "so sach hanh ky thuat toan khoa", "so sanh tranh ky thuat toan khoa", "bo sach tranh ky thuat toan khoa", "co sach tranh ky thuat toan khoa"

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