Google

How to do a search for a specific phrase

Just enclose the phrase in quotes

 "I need to found this string" +"and this too" +"not necessary together"
 

How to do a search for a book

The following will string get rid the regular web pages htm/html using `inurl` in the search string

 -inurl:htm -inurl:html intitle:”index of” +(”/ebooks”|”/book”) +(chm|pdf|zip)
 

How to do a search for specific file type

The colon does the trick, this example will look for pdf files on a directory

 "possible name" :pdf