Perhaps you should try some spelling variations:
"so canh trinh nghien dien hoc" » "so canh trinh nghe dien hoc", "so canh kinh nghiem dien hoc", "so canh trinh thiet dien hoc", "so canh trinh nghiep dien hoc", "so canh trinh khien dien hoc", "so canh tranh nghien dien hoc", "so hanh trinh nghien dien hoc", "so canh tinh nghien dien hoc", "so canh trinh nghien dien hoa", "so canh trinh nghien khien hoc", "so canh trinh nghien tin hoc", "so sanh trinh nghien dien hoc", "bo canh trinh nghien dien hoc", "so danh trinh nghien dien hoc"
"bo sach thieu nhi y hoc" » "co sach thieu nhi y hoc", "hoc sach thieu nhi y hoc", "bo sach thieu nghi y hoc", "bo sach thieu nho y hoc", "bo sach thieu nhi o hoc", "bo sach hieu nhi y 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 canh trinh nghien dien hoc") or ("bo sach thieu nhi y hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so canh trinh nghien dien hoc") OR ("bo sach thieu nhi y hoc")).
• Removing quotes may allow a broader search: (( so canh trinh nghien dien hoc ) or ( bo sach thieu nhi y hoc )).
• Adding a wildcard symbol may retrieve word variants: (("so canh trinh nghien dien hoc") or ("bo sach thieu nhi y hoc"))*.