Perhaps you should try some spelling variations:
presentation method » presentation math, implementation method, preparation method
self presentation » _ presentation
method studies » methods studies, methods studie, method studying
lower birth » low birth, fewer births
new birth » low birth, new north, one birth

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

• Performing a fuzzy search may retrieve terms with similar spellings: commercial ((((longer birth) OR (lower birth))) or (new birth)) self presentation method studies.~.
• If you are trying to use Boolean operators, they must be ALL CAPS: commercial ((((longer birth) OR (lower birth))) OR (new birth)) self presentation method studies.*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "commercial ((((longer birth) OR (lower birth))) or (new birth)) self presentation method studies.*".