Perhaps you should try some spelling variations:
"tu sat trach nhiem du hoc" » "tu sat trac nghiem du hoc", "tu sat trach hiem du hoc", "tu sat trach nghiem dau hoc", "tu sat trach nhiem huu hoc", "tu sat trach nhiem tu hoc", "tu sat trach nhiem duoc hoc", "tu bat trach nhiem du hoc", "tu dat trach nhiem du hoc", "tu hat trach nhiem du hoc"
"su canh tinh nghien du hoc" » "su canh trinh nghien du hoc", "su canh kinh nghiem du hoc", "su canh tinh nghe du hoc", "su hanh tinh nghien du hoc", "su manh tinh nghien du hoc", "su canh tranh nghien du hoc", "su canh tinh nghiep du hoc", "su canh tinh nghien cuu hoc", "su canh tinh nghiem dau hoc", "suc canh tinh nghien du hoc", "su can tinh nghien du hoc", "su anh tinh nghien du hoc", "su canh tinh nghien tu hoc", "su canh tinh nghien duoc hoc"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("su canh tinh nghien du hoc") or ("tu sat trach nhiem du hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su canh tinh nghien du hoc") OR ("tu sat trach nhiem du hoc"))*.
• Removing quotes may allow a broader search: (( su canh tinh nghien du hoc ) or ( tu sat trach nhiem du hoc ))*.