Perhaps you should try some spelling variations:
"phap truyen khai hoc" » "phan truyen khai hoc", "tap truyen khai hoc", "phuc truyen khai hoc", "phap truyen khau hoc", "phap truyen ki hoc", "phap truyen dai hoc", "phap truyen thai hoc", "phap truyen khi hoc", "phap truyen khai thac"
"phap trien khai hoc" » "phap trien nha hoc", "phat trien khai hoc", "phap tieng khai hoc", "phap tiep khai hoc", "phap trien thai hoc", "phap trien khi hoc", "phap trien khai thac"
"phat vien khoa hoc" » "phat hien khoa hoc", "phat dien khoa hoc", "phat trien khoa hoc", "phat von khoa hoc", "phat lieu khoa hoc", "phat van khoa hoc", "phat vien hoa 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: (("phat vien khoa hoc") or ((("phap trien khai hoc") OR ("phap truyen khai hoc"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("phat vien khoa hoc") OR ((("phap trien khai hoc") OR ("phap truyen khai hoc")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"phat vien khoa hoc\") or (((\"phap trien khai hoc\") OR (\"phap truyen khai hoc\"))))".
• Removing quotes may allow a broader search: (( phat vien khoa hoc ) or ((( phap trien khai hoc ) OR ( phap truyen khai hoc )))).
• Adding a wildcard symbol may retrieve word variants: (("phat vien khoa hoc") or ((("phap trien khai hoc") OR ("phap truyen khai hoc"))))*.