Perhaps you should try some spelling variations:
"nhat trien khai hoc" » "phat trien khai hoc", "nhat tien khai hoc", "chat thien khai hoc", "nhat trien nha hoc", "nhat trien khi hoc", "nhat trien khai thac", "nhat trien khai hoan"
"phap trien thai hoc" » "phat trien thai hoc", "phap truyen thai hoc", "phap tieng 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"
"pham tien nha hoc" » "phan tien nha hoc", "phap tieng nha hoc", "phan tieng nha hoc", "pham trien nha hoc", "pham dien nha hoc", "pham mien nha hoc", "pham tien nha thuoc", "pham tien khoa hoc", "pham tien nha nuoc"

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 ("pham tien nha hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nhat trien khai hoc") OR ("phap trien thai hoc"))) OR ("pham tien nha hoc")).
• Removing quotes may allow a broader search: (((( nhat trien khai hoc ) or ( phap trien thai hoc ))) or ( pham tien nha hoc )).
• Adding a wildcard symbol may retrieve word variants: (((("nhat trien khai hoc") or ("phap trien thai hoc"))) or ("pham tien nha hoc"))*.