Perhaps you should try some spelling variations:
"so sach nganh y thuat van hoc" » "so sach ngan y thuat van hoc", "so sach tranh y thuat van hoc", "so cac nganh y thuat van hoc", "so sach nganh y thuat san hoc", "so sach nganh y thuat va hoc", "so sach nganh y thuat ban hoc", "so sanh nganh y thuat van hoc", "bo sach nganh y thuat van hoc", "co sach nganh y thuat van hoc", "so sach nganh my thuat van hoc", "so sach nganh kxy thuat van hoc", "so sach nganh ki thuat van hoc", "so sach nganh y thuat van hoa"
"so sach hanh ky thuat toan khoa" » "so sach danh ky thuat toan khoa", "so sach han ky thuat toan khoa", "so sac hanh ky thuat toan khoa", "so sanh hanh ky thuat toan khoa", "bo sach hanh ky thuat toan khoa", "co sach hanh ky thuat toan khoa", "so sach hanh kem thuat toan khoa", "so sach hanh kmy thuat toan khoa", "so sach hanh kkxy thuat toan khoa", "so sach hanh kki thuat toan khoa", "so sach hanh 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 sach hanh ky thuat toan khoa") or ("so sach nganh y thuat van hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach hanh ky thuat toan khoa") OR ("so sach nganh y thuat van hoc")).
• Removing quotes may allow a broader search: (( so sach hanh ky thuat toan khoa ) or ( so sach nganh y thuat van hoc )).
• Adding a wildcard symbol may retrieve word variants: (("so sach hanh ky thuat toan khoa") or ("so sach nganh y thuat van hoc"))*.