Perhaps you should try some spelling variations:
"nhat trien khai hoc" » "nhat tien khai hoc", "chat thien khai hoc", "nha triet khai hoc", "nhat trien nha hoc", "nhat trien khi hoc", "nhat trien khai thac", "nhat trien khai hoan"
"phap trien thai hoc" » "phap truyen thai hoc", "phap tieng thai hoc", "phap tiep thai hoc", "phap trien thi hoc", "phap trien thanh hoc", "phap trien thuat hoc", "phap trien dai hoc", "phap trien bai hoc", "phap trien hoi hoc"
"phat trien khoa hoc" » "phat trien nha hoc", "phat trien hoat hoc", "phat vien khoa hoc", "phat trien hoa hoc", "phan trien khoa hoc", "pham trien khoa 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: (((("nhat trien khai hoc") or ("phap trien thai hoc"))) or ("phat trien khoa hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nhat trien khai hoc") OR ("phap trien thai hoc"))) OR ("phat trien khoa hoc")).
• Removing quotes may allow a broader search: (((( nhat trien khai hoc ) or ( phap trien thai hoc ))) or ( phat trien khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (((("nhat trien khai hoc") or ("phap trien thai hoc"))) or ("phat trien khoa hoc"))*.