Perhaps you should try some spelling variations:
"te sach nganh y thuyet hoa hoc" » "te sach ngan y thuyet hoa hoc", "te sach tranh y thuyet hoa hoc", "te cac nganh y thuyet hoa hoc", "te sach nganh y thuyet va hoc", "te sach nganh y huyet hoc hoc", "te sach nganh ly thuyet hoa hoc", "te sach nganh li thuyet hoa hoc", "te sach nganh ly huyet hoa hoc", "toc sach nganh y thuyet hoa hoc"
"thu canh tranh kkxy thuat van hoc" » "thu canh tranh kxy thuat van hoc", "thu canh tranh ky thuat van hoc", "thu canh tranh kkxy thuat san hoc", "thu canh tranh kkxy thuat va hoc", "thu canh tranh kkxy thuat ban hoc", "thuc hanh tranh kkxy thuat van hoc", "thu cong tranh kkxy thuat van hoc", "thu ban tranh kkxy thuat van hoc", "thu canh tranh kkxy thuat van hoa", "thu canh trinh kkxy thuat van hoc", "thu canh thanh kkxy thuat van hoc", "thu canh tran kkxy thuat van 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 nganh y thuyet hoa hoc") or ("thu canh tranh kkxy thuat van hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach nganh y thuyet hoa hoc") OR ("thu canh tranh kkxy thuat van hoc")).
• Removing quotes may allow a broader search: (( te sach nganh y thuyet hoa hoc ) or ( thu canh tranh kkxy thuat van hoc )).
• Adding a wildcard symbol may retrieve word variants: (("te sach nganh y thuyet hoa hoc") or ("thu canh tranh kkxy thuat van hoc"))*.