Perhaps you should try some spelling variations:
"so sanh hanh ky thuat van hoc" » "so xanh hanh ky thuat van hoc", "so danh thanh ky thuat van hoc", "so ban hanh ky thuat van hoc", "so sanh hanh ky thuat san hoc", "so sanh hanh ky thuat va hoc", "so sanh hanh ky thuat ban hoc", "do sanh hanh ky thuat van hoc", "so sanh hanh kem thuat van hoc", "so sanh hanh ky thuat van hoa"
"so sach nhan ky thuat tin hoc" » "so sach nha ky thuat tin hoc", "so sach han ky thuat tin hoc", "so sach ngan ky thuat tin hoc", "so sach nhan ky thuat tien hoc", "so sach nhan ky thuat tinh hoc", "so sach nhan ky thuat tim hoc", "bo sach nhan ky thuat tin hoc", "co sach nhan ky thuat tin hoc", "hoc sach nhan ky thuat tin hoc", "so sach nhan y thuat tin hoc", "so sach nhat ky thuat tin hoc", "so sach than ky thuat tin hoc", "so sach nhan ky thuat sinh hoc"

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

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