To search the databases you will need to think of keywords or phrases and combine them with connectors.

It is not possible to type in a long sentence with a question or hypothesis about your topic.

The connectors are: 

And  will find both words or phrases in the same record : World Heritage Convention and World Heritage sites and climate change

 OR  will find either term WHO or World Health Organization  EU or European Union  NPT or nuclear nonproliferation treaty

And and Or searches may be combined:

United Nations Security Council and (Syria or Yemen)

 While failure or success might be used in articles or books, other terms may also be used.

For example, if you are searching for how effective a protocol or program has been over time:

strength, weakness, evaluation, further efforts, loophole, problem, re-examine, unforeseen consequences, gap or gaps,  room for improvement, or retrospective might be used in the article text or headline/title.

Many databases, including Google Scholar, allow you to set up an alert or alerts so that your search/es will be re-run at scheduled times and any new results will be emailed to you.  

This is a time saver and also helps keep you up-to-date on events.